Fan reaction to this dramatic redevelopment has been wildly mixed. Whilst it certainly has had its vocal supporters, it has also incurred an outraged reaction from many quarters with many feeling the decisions made around which aspects of canon to retcon or recreate are haphazard, inconsistent and sloppy. Fans are reacting strongly against many of the costume redesigns as well as other emotionally-charged changes such as Lois and Superman no longer being married and Barbara Gordon walking again as Batgirl. 

The costume redesigns have been following an aesthetic intended to be hip, modern and urban but often resulting in changes that look generic, ugly and plain in comparison to the beautiful and distinctive designs that helped make their characters iconic and memorable. 

Arguably, one of the characters most negatively affected by this new conceptual approach has been Harley Quinn.

If you're on this website, then you know the deal: introduced on the B:TAS show of the nineties, she quickly skyrocketed to cult status, adored by fans of all ages until DC saw fit to further capitalise on her popularity by introducing her to the comics as well. She has maintained cult status ever since, enjoying a degree of recognition and adoration only a few comic book characters have ever had, even those who've been around the past seventy years. A recognised seller, much merchandise is created around the character and tends to fly off the shelves, quickly becoming prized rarities. DC is well aware of her broad market appeal and she has become synonymous along with other key characters in the Batman franchise. 

Harley's highly recognisable silhouette and distinctive costume is well regarded, not only for its flattering, attractive and memorable look but for how effectively it evokes and communicates the character's key traits and qualities. Like Superman or Wonder Woman, Harley's costume is iconic and instantly identifiable. 

Yet Harley was one of the characters chosen for permanent redesign amongst DC's pantheon of legends. 

When asked about the direction he took his redesign in, Jim Lee stated, paraphrased, that people had liked the Arkham Asylum (VG) design and so he was inspired by that. This seemed to be the only justification for taking this design in so wildly tangent a path from everything fans had come to know and love about Harley Quinn. 

Upon its release, the internet was surged with angry outcries from devoted fans who could see no rhyme nor reason for this painfully nonsensical design. Fans' objections ran the gamult from criticising the impracticality of the outfit, to its grotesque hyper-sexualisation to how ugly and generic it is compared to the original design to how little it seemed to speak of the personality of the character we are all so dedicated to. 

In interviews I did at the time, I made the following comments regarding the redesign and the potential impact it has on fans, which goes beyond simply a new look for our favourite character:

"Harley’s costume is a huge part of her appeal because it speaks so profoundly about her as a character. It’s also elegant, classic, distinctive and beautiful. Furthermore, practically speaking it’s comparatively modest – which makes it a great option for cosplayers who don’t want to dress skimpy and an ideal choice for round-year conventions. The new costume is not only impractical; it’s ugly and generic and says nothing about Harley as a character."

"Mainly what I hate is how unimaginative and generic-looking it is. Harley's classic costume is absolutely unmistakable - she has one of the most recognisable silhouettes out there. That original design is really elegant, striking and beautiful - not to mention it translates to reality really easily. 
This redesign has Harley looking like just another face in a crowd of try-hard wannabe-goth posers. It demonstrates none of her zany personality, her charming quirks or playful nature. Another thing about Harley and her personal fashion aesthetic is that she's sexy and cute, but pretty conventional - peaches & cream skin, straw-blonde hair, big blue eyes - she likes to dress cute, comfortable and stylish. This redesign does not reflect that at all - she's not the sort of dame to mix her hair colour up like that. She's not ghost-white. She radiates all-American girl-next-door health and vitality. This redesign evokes none of that. 
Finally, part of the charm and appeal of Harley's classic look is that, as a character, she's pretty deceiving. She looks all playful and fun, just a little mischief with no real harm intended - right until she crushes your skull in with her mallet. Personally, I find the cutesy bombshell who no one takes seriously - which is kinda her edge - until she snaps and starts blowing things up - to be a lot more intriguing and "dark" than someone who looks like they raided Hot Topic's clearance bin to rebel against Mommy and Daddy for not letting her go on that camping trip with her boyfriend. 
Finally, it just doesn't stand out. It's like any other super-revealing, impractical, unimaginative female character costume that comics are saturated with. The best costumes are the ones you recognize instantly, that have iconic style. Harley's classic costume has that in spades. Furthermore - it's just not practical. Come on. The first time she does a back-flip, you can kiss that PG-rating goodbye. "

Whilst writer Adam Glass consistently promised fans Harley's new direction would make sense with the revelation of her origin (in itself an upsetting premise to fans, who are very much attached to her origin as laid out in Mad Love), fans have thus far not been impressed with what's on offer. From interviews and discussions, Glass clearly has the right ideas about Harley, enough to have a good grasp of her character and identity but how it's played out on the page has been dissatisfying and contradictory not just to Harley's previous established personality but also to what Glass himself has had to say about the character. Upon its release with the revelation that Harley is hellbent on proving herself to the Joker, I had this to say:

I’ve always said I will pick up this book, because I collect everything Harley and always have. I remain dubious and critical of the relaunch over all and I think a bunch of bad character choices have been made, but I always concede to what I feel fits in and makes sense. I happily ate my hat when the Joker graphic novel turned out to be better than I expected but I still maintain my criticisms of that (which doesn’t preclude my ability to enjoy it - hey, I love the Chucky movies, okay!) and I still think a lot of the decisions around this relaunch are BAD. 
Like with the last writer on Gotham City Sirens, I felt much of the time that the writer understood where he needed to go with the characters but didn’t understand how he needed to write them to get them there. So he took them to the right point - but wrote them out of character doing so, if that makes sense. Sometimes he hit the mark right on, other moments just rang hollow and false. 
That’s how I’m feeling about the relaunch right now - they know what they need to do to maintain characterisation, but are jamming the characters into these contrived set-ups to meet the relaunch specifications. 
I will never, however, ever, EVER agree Harley’s costume change is a good idea, in character or serves the character. If this relaunch were, in fact, an elseworlds story or a continuity for a new series, it would be different - I would still hate the costume but, as with Arkham City, Arkham Asylum, Joker, etc I could accept it as it’s set within a different world. But for this to be the mainstream? No. No, it’s wrong. I will never back down on that. It’s NOT ‘just a costume’. Costumes reflect characters. Harley’s costume was a key statement about her character and was part of what made her so accessible to so many fans - including very young girls. And that IS important. 

Exception was paticularly taken with the insinuation given by Harley herself that she'd had a long list of criminal bad boyfriends in the past. I gave voice to my own objections on that score with the following:

"Harley’s objectives as a medical student and a doctor were both self-centered and selfish. She had an ambitious goal and was calculating and deliberate in her pursuit of it. She would NOT have risked her intentions for the sake of some cheap thrills with a bad boy, or even a lineup of them. That’s the whole POINT. That Joker bamboozled her so intensely, his seduction of her so complete that she was willing to sacrifice self-interest and normalcy for is sake. THAT’S part of the intrinsic drama of the whole story. Harley wasn’t a “good girl” BJ (Before Joker), but she was careful because she wanted to attain celebrity-status in a ‘sanctioned’ way. But love became her mission instead - their attraction and interest in each other (and make no mistake this was mutual - he fucked with many doctors but he didn’t mould them all into his image) was powerful enough to derail her life-path to that point and set it off on a completely different course. She attained a kind of celebrity-status still, but lost everything else. And she’s okay with that because what she gained, from her perspective, was far greater. That’s what makes their love story so intense, so dramatic, so unique, so tragic AND so beautiful. It’s simply NOT in line with this progression and character that a random list of villainous thugs would’ve preceded Joker."

"Harley pursued psychiatry to attain fame, using less than ethical means. But the Joker was her first lapse into pure insanity, into crossing the line between normalcy and madness. That’s what makes it dramatic. There wasn’t a ‘pattern’ of bad guys, part of the heady appeal of the Joker in her life was he being something so outside her experience until then. It wasn’t just a series of bad boys escalating. It was a dramatic, powerful shift from one life to another. There were indicates of aptitude for it in her normal life, but she was fame-hungry - she was being careful. She was concealing her real self. 
Making the Joker just one more in a list of crims and thugs lowers the drama of her story and doesn’t jive with her psyche anyway. Harley’s shift into her life of crime was a transformation. Making out all her previous boyfriends were all “TRULY BAD” - which is a really BIG thing to claim - demonstrates no progression and no transformation. 
As for the second exchange… ARGGHHHH. That implies that she has ALWAYS let herself be defined by her boyfriends when this PATENTLY isn’t so. SHE was defining her life pre-Joker - by going after what she wanted, creating herself into what she wanted to be as a psychiatrist. I really doubt any GUY was going to get in her way then. The one who eventually did so orchestrated a campaign of psychological manipulation over months of intimate time together. Ambitious little Dr Quinzel did not have TIME for guys to do that prior to her internship at Arkham - and certainly not whilst there! Until it was sprung on her unawares… 
Again, the TRANSFORMATION is the point. From one thing to another."

Most recently at time of this writing (18/03/2012) the latest development to upset fans has been the much-dreaded new origin. Harley's heretofore unexplained white skin and parti-coloured hair as well as her original connection with the Joker have been explained. Whilst fans are somewhat divided as to the characterisation in the unfolding of her scenes as Dr Harleen Quinzel with the Joker, all Harley's most devoted fans are united in their disdain for her 'transformation'. In opposition to the slow seduction and warping of her mind throughout many months of therapy with the ultimate self-actualisation in Harley Quinn, after only a few exchanges the Joker dipped an unwilling Harley in the same vat of toxic goo that transformed him - leaving her in her current incarnation. 

Rightly, fans feel this plot device is lazy and lacks the drama and pathos of the original. Fans left their opinions on the official page for the issue on DC Comics' website. 

However, it is worthwhile noting that writer Adam Glass would've been obliged to create an origin that explained Harley's new look which would somewhat have limited his options. The same goes for all creative teams working on DC books right now - ultimately they have to fall in line with the directives handed down by the group who decided on all the imposed changes. Certainly the stories are not completely without merit. There are moments that are intriguing and ring true for character, that are enjoyable and provoking; certainly some of the ideas that Glass has conceptualised have a lot of potential and demonstrate a keen interest in the character and desire to do something substantial with her. Perhaps the biggest issue is the obligation to confine the story to the new parameters as defined by the head honchos at DC Comics. 

As to why Harley Quinn needed a new origin at all - well, one could very well ask that with regards to the many beloved characters whose classic histories have been tampered with. DC seem to feel it's a necessary move, despite the dissent of fans. Indeed, one might wonder if DC's priority has become wholly the securing of a new audience rather than maintaining the loyalty of the existing one. Time will tell how well these changes sustain and who will stay, who will go and who will join up. Many Harley Quinn fans have already dropped the Secret Six title - will this radical new direction of DC's prove to be a short-term publicity stunt along the lines of Knightfall and Blue Superman - or are DC determined to make it stick, no matter what? 
Notable fan reactions that are worth pursuing include the following:
Harley and Her Costumes
DC, What's Wrong With This?
Long List of Boyfriends?
Something I Needed To Get Off My Chest
Perspective from a Deadshot fan
Bad Direction
So I Just Read The Newest Issue of Suicide Squad (with some commentary by me)
Give Us Back Our Harley
What Have You Done, SS
I'm Numb