Biggest complaints I see are:
1) It has a laugh track (or, argue some, it is filmed in front of an audience, but it doesn't matter either way).
Is this a problem? I don't think so. I grew up watching shows that had laugh tracks/were filmed in front of an audience and barely notice it. Does it influence what I laugh at? Probably, to some extent, though I do find myself laughing at things the laugh track/audience doesn't. I don't mind this.
2) It makes fun of geeks.
No doubt it does, but I don't think it is as pervasive as people suggest it is. I think the bigger issue is that we do ridiculous, embarrassing shit just like the guys on the show and don't like being shown what we look like.
3) Some of this shit is getting old.
Certainly, but I'd say this is more annoying that show-destroying. They need to find something for Raj to do that doesn't involve an endless stream of gay jokes. The same goes for Stewart, who has gone from a halfway decent character who appeared every so often to a sad-sack who shows up all the time to depress everyone. One could complain about the ups and downs of Penny and Leonard's relationship, but there has been development for the past two seasons. Same for Shamey's relationship.
4) The women ruined it.
No, they didn't. Integrating Bernadette and Amy has, if anything, improved the show.