I don't think its a classic but it's definitely a more interesting movie than the first one. It's Burton with no restrictions doing what he wants. It's a gothic Christmas movie that is really pretty to look at and has some cool themes. Isolation, neglect, the nature of being a misfit, corruption, family, etc but it never really nails any of them. It's all over the place in that sense. There's an interesting idea of Oswald and Bruce being of the same ilk...until it's dropped. There's an interesting idea of Bruce and Selina being the same...but it's only given light for two scenes. There's another interesting angle of bruce being jealous penguin is taking that title of Gotham's favorite son. Also, they give lip service to bruce having trouble reconciling his own duality, but because the movie is barely focused on him at all, that too is thrown to the wayside.
Batman Returns has a lot going for it visually but none of the ideas really add up. Plus the penguin vacillates from a tragic figure to a damn sexual assaulter at the drop of a hat. Catwoman is the strongest part of the movie and I'd say her arc is the most complete and complex