I disagree with people taking credit away from Schumacher for the serious parts of BF, it was all Schumacher's movie, Burton had nothing to do with the movie past that script writers meeting and being a producer in name only. The answear here (as much as people want to believe the opposite) is that Schumacher cared for the movie in the sense that he wanted to tell a story while yielding to the studio's requests, thats why Forever has good stuff there because its director allowed for that (he is the captain of the ship after all) and was going to be even better but the studio mandated the film to be cut down.
Now, after the success of Forever and the preasure to follow it with an even bigger and more family friendly film came in, I guess Schumacher said "f#$% it, if this is what you want then have it" and went along with it, which he probably shouldn't but he did and must regret it doesn't matter what he says about it.
I have always agreed with Chris O'Donell remark that BF actually felt like a movie while B&R was merely a toy commercial.