To be fair though, he has done that sometimes - just not often enough. The best example, I think, is Stick To Your Guns - Jon didn't even know the words, and had to read them from the banners, but he went with it.

I know that some bands vary their setlists a lot more than Bon Jovi do, but the fact that they do at all is a good thing. Some bands literally play the same show night after night.