Schumacher is actually a very talented director. His litany of impressive work contrasts with the two Batman films he directed which make me think he was definitely pressured by the studio. I mean, how you go from directing movies like The Lost Boys, Flatliners, A Time to Kill and then direct two flashy, campy films is beyond me. He may never wanted to direct an adaptation of Batman: Year One but I definitely think had he been allowed to, he could have delivered a dark Batman film.
Don't forget "Falling Down" - An excellent movie with one of Michael Douglas's best performances. I can't resist defending Val Kilmer whenever people put down his performance in "Batman Forever". I think he always gets overlooked because people have this nostalgic attachment to Keaton and Clooney has gone on to prove himself as one of the most dependable American actors with a great career, but I think Kilmer did a really good job. Batman creator Bob Kane even liked him as Batman more than Michael Keaton and I agree with him. I also liked his Bruce Wayne more than Michael Keaton's.
I thought Keaton acted too weird as Bruce Wayne, like that scene where he says, "you wanna get nuts?". People have defended it as Wayne trying to be heroic and save Vicki Vale in the only bumbling way he could without giving away that he's Batman (kinda like Christian Bale acting like an ass insulting people at his party or allegedly trying to catch the traffic light in his car), but I don't buy that. I just saw it as Keaton playing his quirky persona that he'd established in "Beetlejuice" rather than doing something organic to the character.
Val Kilmer should have played up the carefree millionaire persona more (he was pretty much serious the whole time, whether he was Wayne or Batman, aside from that weird moment where he smiles as Batman and the "drive thru" line), but I thought he fit the part more than Keaton overall. The only real wink link in "Batman Forever" acting-wise was Tommy Lee Jones, who simply had very little to work with given how his character was written.