Fourth edition Dungeons and Dragons has generated a lot of controversy. Some people love, some hate it, and some go so far as to claim it's not really D&D. I have no real opinion about the game for the most part. From what I can tell, it's a good game for what it does, but that's not the kind of thing that I like. However, I haven't played it that much, so my opinions on it are not strong.
One thing, however, bothers the shit out of me about D&D 4E: Wizards seems to have done little (or bad) playtesting. Quite a few things about the original game didn't work very well, and had to be corrected. The most extreme example I can think of is skill challenges. Literally within a month or so of the first 4E books coming out, Wizards issued a set of errata that quite dramatically changed skill challenges. Given that Wizards is by far the biggest RPG company, and they had ample time to playtest it, this is inexcusable. They should've known that skill challenges as written in the original Dungeon Master's Guide didn't work. It seems like they just decided that they would have the players who paid for the game playtest it.
There are other examples as well. I've heard from a number of gaming podcasts and blogs that several classes have been rather significantly rejiggered because they didn't really work that well when they came out. And other people have said that basically the design team didn't seem to really understand class design until at least Players' Handbook II, almost a year after the original release of the game.
These problems all could have been discovered with adequate playtesting. I wonder, though, if Wizards did some of this on purpose. The big money maker for 4E isn't the books, it's the subscription the the online service Dungeons & Dragons Insider (DDI). One of the key benefits of a DDI subscription is that it has all the game rules available online--and they're updated regularly. This makes me wonder if the whole business plan is to sell people something that wasn't carefully playtested on purpose so they could make more money on the subscription with the correct rules. If that's true, then that's just scummy. And it shows that the design goals of 4E weren't about making a good game, but about making money.
I don't know if Wizards is that sinister; in general, I think you shouldn't attribute something to malevolence that could be the result of incompetence. At the very least, though, the original publication of D&D is flawed, by Wizards' own admission, and you have to keep paying them to get the corrected version. That's not something I want to be a part of.