Boy, is THAT a loaded statement around here. And from a moderator, too!
At the risk of seeming provocative: Really? Worse than Batman & Robin?
There's a difference between worse Batman film and worse film in general.
Batman and Robin at least tried to be a Batman film. I at least feel like I am watching a movie with Batman in it. It absolutely failed as film though and is a piece of garbage, but at least it's a Batman movie at minimum. It was bogged down by trying to modernize an out of date version of Batman (the Adam West version) and movie executives seeing the film as an advertising venture first and foremost as opposed to being a true film.
Batman Returns on the other hand didn't even try to be a Batman film, it was a Tim Burton film the same way that Edward Scissorhands, Beetlejuice, and the Nightmare Before Christmas are Tim Burton films. Unlike the first Batman film which felt like a combination of a modernized Bill Finger/Bob Kane Batman with Tim Burton's visual flair, Batman Returns was a balls to the wall, absurd, extremely Gothic, Tim Burton film. Asides from the whole Batman motif, there is nothing about Batman Returns that feels like Batman. You can replace Batman with any generic vigilante and you would still have the same film. Even the producers have admitted that they see it as a Tim Burton film first and foremost as opposed to being a Batman film. Burton really had no desire to make a real Batman film after the first one.
That said, as a film though, Batman Returns is absolutely brilliant. The cast is amazing, Danny Elfman's score is amazing, the visual style is amazing, I love the plot, I love the characters, I love how dark the film is, and I just love how absolutely absurd and goofy everything is in the film. Even though it's a really ****** Batman film, it's just an absolutely amazing film and dare I say, Tim Burton's best work.
Is Batman and Robin a better Batman film than Batman Returns? Yes. But is it a better film in general than Batman Returns? Hell no! Batman Returns is easily in my top 10 of movies. I love it more than Tim Burton's first film. Batman and Robin though is in my top 10 worst movies ever made even though it is an actual Batman film.