I can't find a copy of the interview in question, but someone once asked Rumiko Takahashi why Nabiki Tendou, a girl who in the first couple of chapters of Ranma 1/2 seemed to be a fairly normal Japanese girl, turned into a money-loving shark who would gladly sell out her family and friends and seemed to have no conscience or soul. Takahashi's answer was "because it's funny."
I was reminded of this while reading Stefan's post yesterday. Much of what I tend to think of as Ranma, including many characterizations that are almost thought of as canon these days, was never actually used by Rumiko Takahashi in the canon material. It was stuff invented by fans for their fanfics in order to make the characters easier to write, give a third dimension to, or just make more bearable. So we got 'fanon': Nabiki uses the money she extorts to finance repairs to the dojo, for example, or Kasumi being far more savvy than she lets on and using her yamato nadesico persona as a front. And yes, it could go the other direction as well: Akane hits Ranma because she is mentally unstable and needs psychiatric care.
See, Takahashi gave us, in both Urusei Yatsura and Ranma, great characters who it's easy to love. We want to see them succeed, we want to laugh at their stupidity. But they are not fleshed out. They aren't three-dimensional. They don't feel real. They feel like characters in a goofy shonen manga that will do anything for a laugh. This is not necessarily a bad thing. Comedy is not pretty. It's simply funnier to watch people be horrible to each other, and much easier to do so if they all can fall into basic patterns of behavior. Akane will jump to conclusions and hit Ranma. Ranma will say something insulting and thoughtless. Lum will get jealous and zap Ataru. These are the cornerstones of the series. And over the course of the series, while there is slight forward progress, if it has to be sacrificed so that we can see a huge pile of cast members screaming and hitting each other? So be it.
Of course, both UY and Ranma were turned into successful anime. Like all anime, they had to find ways of expanding the source material: if you animate 16-page chapters for a series, you'll run out of material far quicker than you'd anticipate. Some of the ways they did this involved the characterization: the characters were softened, and didn't seem to be such moral vacuums. At the same time, their traits were exaggerated for the comic effect that animation can provide. So you have Akane hitting Ranma even MORE. And it's the anime, more than the manga, that fans are familiar with. As a result, these characterization seemed to stick more than the manga ones, even if they're sort of once removed.
The same thing happened with Urusei Yatsura, where Mamoru Oshii, the series director for several seasons, had several battles with Takahashi about the direction of the series. And indeed, if you watch the UY anime Ataru, Lum, and the others get several 'Awww, they're really sweet after all!' moments that just aren't in the manga itself. Not to say the manga never had those moments. But they were much less common, and I think Takahashi preferred her characters to be petty, vindictive, and spiteful in the long run. That made plotting and comedy easy.
Comedy's hard to write. Much easier to be dramatic. As a result, when you take series that give you some fun and fascinating characters, but then don't do anything with them (no one reads UY or Ranma for the plot), and throw in an anime that sometimes exaggerates or softens said characters depending on the director or episode... well, you've got a recipe for fandom controversy. Bashing and Ship Wars didn't start with Bleach, after all. Writing realism into Ranma and UY became a common theme in the mid to late 90s, and continues on a smaller level to this day. And if you try to realistically write a girl who habitually punches a man so hard he flies several city blocks... well, you're going to have issues.
(On a side note, this is one reason why, much as I love it, I have some problems with Maison Ikkoku. Takahashi essentially did the same thing as Ranma fanfic writers, which is taking her wacky characters and placing them in a setting with far more realism, and realistic leads. Godai and Kyoko, however, despite their faults, were no Ataru and Lum. They were sympathetic people we really wanted to root for. As a result, when Mrs. Ichinose, Akemi, and especially Yotsuya messed with them for the lulz, I got a lot more irritated then I would at UY or Ranma characters. It just felt like it hurt more.)
I was unfamiliar with the concept of 'bashing' till I got into Ranma fandom. I didn't see it quite as much with UY (though it was there), mostly as most fans liked the pairing of Ataru and Lum, and there were never any realistic rivals presented for the fans to argue over. Ranma, though, with the introduction of Shampoo and especially Ukyou, had alternatives. Both were harem series, but Ranma is a harem series in the modern definition: nothing ever gets decided, and the fans argue about who the lead guy will end up with till it dissolves into a screaming match. UY and Ranma both had 'semi-open' endings, where Takahashi implied that the couple would eventually get together... but didn't actually show it. Therefore there is, in the mind of many, no canon pairing: Ranma and Akane did not get together in the end, therefore they are NOT together.
And yes, other characters got bashed as well. When you take a series about a bunch of insane goofy teenage martial-artists seriously, you suddenly realize "Hey, she's a psychopath!" or "Hey, his motivations are guided by a misplaced hatred!". Psychoanalyzing to death is the order of the day. It can make for good drama - hell, I did it myself back when I wrote Ranma fanfics. But it can also have some unfortunate consequences. There's a line running from Ranma through Love Hina right to Harry Potter, a line which has fanfics whose basic plot can be described as 'Lead male gets a backbone, decides to man up and shows the girls who've been tormenting him what for'. Part of this is a side consequence of weak male leads, which at least Ranma does not have to deal with. But it gets a bit unrealistic when the cast starts behaving in ways that are not remotely close to the source material. And much of it is driven more by 'I hate Angry Girl X' and shipping than anything else.
In the end, I started to ask myself, is it okay that Ranma and UY are essentially two-dimensional? They don't have depth of characterization, even though they have great characters. There is no hero's journey. Ryouko Mendou is hurling grenades and laughing like a loon in the final volumes, just as she did in her first appearance. But it's still funny. And there is a wide variety of plots, especially in UY, where it seems that Takahashi could never stop thinking of insane material that made me impressed at her twisted mind. (A robot alien teacher shaped like a chalkboard eraser?) It's a question of what one wants out of the material. Do you want wacky, Osaka-style comedy shenanigans? Well, you are the reason Takahashi is one of the richest manga authors in Japan. If you're watching or reading Ranma or UY for the romance, or to see Akane come to terms with the fact that Ranma isn't a pervert and she should stop leaping to conclusions... then she must be a very, very frustrating author for you. Perhaps you should write a fanfic about it?