I will defend Batman Forever with my dying breath.
It was just the right amount of pretentious, gothic, and campy. If you go in expecting a serious modern Batman movie, you're in for a bad time. As long as you go in expecting an absurd homage to the equally silly 60s show, mixed with a more modern self serious take, all of it straight-faced, you can enjoy it just fine. It's tonal whiplash but it's fun.
You got Jim Carrey in his prime, Tommy Lee Jones going full ham, both of them devouring every last inch of scenery. You got Nicole Kidman awakening something in every prepubescent boy, and a few girls too (and that's where we get the People's Joker from).
It also had the balls to give us a genuine attempt at Robin. Something the movies have been too chickenshit to do for nearly 30 years.
Now Batman and Robin...that's where they took it too far. The balance was way off, way too cartoonish, with nothing to counterbalance it. It's so painfully and obviously a toy commercial, in every way.