Keep in mind that Joel Schumacher wasn't entirely responsible for the two bad Batman movies. Up until that point, he was a respected filmmaker (still is, if you leave D.C. Cab, his Batmans, and The Number 23 out....I mean, come on, St Elmo's Fire, Lost Boys, Falling Down, Flatliners, The Client, A Time to Kill, Tigerland, Phone Booth).
Warner Bros was upset with Tim Burton's dark film Batman Returns. They wanted to sell toys, and a lot of parents complained about images of The Penguin on their kids McDonald's cups. WB had a much more kid-friendly image in mind.
If you ever have the chance (I haven't), listen to the commentary for Batman and Robin. It's one long apology from Schumacher. What I have heard of it is great. He's very humble.