To be more accurate, it was WB and McDonalds that decided on making the films to sell toys, Schumacher actually wanted to make a serious Year One adaptation.
Yeah, but he did make Batman Forever. And Batman and Robin. I think Schumacher is a great visionary director but the lesson is: if you eat ****, you stink. You can't come back afterwards and say you really wanted to do something else. He did what he did. I'm sure he made a lot of money. I am also sure he cried all the way to the bank.
Forever is less of a train wreck than B&R. I think Kilmer was at the height of his career and he suddenly found out he had signed up to be in a 1,5 hour toy commercial and he didn't like it one bit. There's that famous quote from Schumacher.
Schumacher later did Tigerland which proved that he is an amazing director. He should have walked from Forever and B&R but it's easy being clever in hindsight and I'm sure when he signed he thought that this would help his career.
I love Kilmer and thought he brought the Batman some soul. He tried. If Schumacher had been allowed to do the dark film he wanted to do and Kilmer had starred in it, I think it would have been awesome.