I'm also of the opinion that you don't really need to know a lot about the other guy. Some things, sure, but a couple of minutes of research should usually be sufficient.

I think most of us do a pretty good job of expressing who our characters are in our writing. If you were facing me, for instance, you'd know Vinnie is the champ. You could see his title history, his win-loss, etc, and say okay, Vinnie is the top guy. The rest you'd probably b able to easily get from whatever recent things I've written.

A lot of guys are of the 'gotcha' mindset, where you want to prove the other guy wrong - to me that's never been fun. Some think it's the way to go though.