I didn't know he was ever all that great. Sure clerks was fun because he talked about star wars and stuff, and mall rats was funny because of Brenda and all that. But it was all just silly pop culture stuff. All his other stuff was just an attempt to recapture that. Don't get me wrong, I like his stuff. He's just never been all that great.
I'd strongly disagree. Dogma is a wildly different film, thought it may have the "dick and fart joke" feel, it is an incredibly well crafted movie, and a serious love letter to Kevin Smith's belief in God over organized religion.
People are also quick to dismiss Jersey Girl due to the fact that Jennifer Lopez and Ben Affleck are in the film together and it came out at roughly the same time as Gili, but I found it to be an incredibly heartwarming movie, if not a bit cliche.
Zack and Miri failed on multiple levels. It was too sweet to appeal to the clerks/mallrats croud, but to vulgar to appeal to the mainstream crowd.
I also agree with other posters in that I loved the hell out of Red State.
He has been incredibly hit or miss outside of the Jay and Silent Bob films, but really, what writer/director doesn't have the occasional bomb?
As was pointed out earlier, Kevin Smith only directed Cop Out, and had nothing to do with the writing of it. I'm not saying it was great directing on his part, but I don't know if it would have been a good movie no matter who directed it.
As for his attitude, we've had this discussion multiple times and it's hardly worth rehashing. Whether you think he's an asshole/whiner/whatnot should be seperate from your analysis of his films.