That's why you should all play Dead or Alive. >_>
jk jk
They were talking about this at doacentral and some people were for it, others against it. Personally, if they aren't broken characters or anything, I don't see there being a huge problem with them being added into the game. However, I think they look a bit silly and don't fit in very well.
As for there being a sellout part in the game to ruin it, DoA4 has Spartan and there is still a good community (just not in OK; try the east coast lol). There are only a handful of people that use Spartan and even the top Spartan player in the community said that he doesn't use her because it's Spartan; he uses her because he likes her playing style. If it's a good game, I don't think you have to worry too much X_A. I mean, didn't SC2 have gimmicky characters (gimmicky meaning not a part of the usual cast) and yet the game was still good? Or I could be wrong. I didn't get into SC2. >_<