You guys have to realize that BJ has been doing this for awhile. He has always been up and up with the latest and greatest things out there - he and his brothers knew about the de la riva and x-guard before anybody else did here in hawaii, he is constantly working on different aspects of his game... even if you don't think that he is evolving his approach, he is, but it is a little more subtle than a complete revamp of his fighting style where all of a sudden he's going to be doing thai boxing instead of american (though he has studied thai boxin extensively)
It is easy to see him as lazy because he has lacked cardio a few times, but the one aspect of his preparation where he is not (and obsessively so) is in his approach to evolving his techniques.
He doesn't like to utilize leg kicks because he doesn't want to expose himself to easy takedowns. He feels that boxing is the best way for him to set up the rest of his offense (takedowns, etc) and he utilizes that very effectively.
Basically he fights the way he does because he feels that leaves him the least exposed and that there is continuity between his striking and grappling. It is not because he is unfamiliar with the other aspects of the game.
He did have obvious problems with GSP, but Kenny cannot count on the same strength and size advantages that GSP had...BJ will probably be the stronger of the two.
My fear in this fight for BJ is that Florian is a tough fighter, and while BJ will probably start off strong, if he is unable to finish K-flo in the first couple of rounds (which may be hard given Kenny's durability,) Kenny will still be ready to fight in the last three.