All his movies are the same, large cast of characters that don't know each other, world-ending disaster strikes, monuments are destroyed, entire cast comes together to save the world. 2012 is no different.
And yet, I love all these movies!!!
I wouldn't say they're all the same, though many of his films do share similarities.
Some are decidedly better than others. Independence Day, for instance, is excellent. 2012 is kind of shitty. The Day After Tomorrow falls somewhere in the middle, as does Stargate.
I'll also point out that every once in a while he'll do something completely different, like The Patriot or Anonymous.