In the cartoon, Hulk was potrayed as the villain, and it works well.
With the same formula turned into live action, and with proven success of Iron Man and Incredible Hulk movie, I think the idea will continue to be awesome

Avatar didn't pretend to be anything it wasn't. It was simply a grandstand event movie with a simple and effective story to tell. It's not a serious sci-fi epic. Manage your expectations.

The Avengers doesn't pretend to be anything other than a loud, dumb, big summer blockbuster. And it's done right enough that it yields quite a bit of fun for me.

But let's not kid ourselves here. Neither brought anything new to the table (I'm not talking about 3D, which I don't care about). Both movies ticked the usual boxes for their respective genres, but they don't do anything beyond that.

Plus I still don't see what's so uniquely Whedon about it. All I hear is about the dialogue but I don't feel it's anymore witty or sophisticated than, say, Iron Man. In fact, some of the lines were pretty cringeworthy.