The way he lauds TOS and so decries the other Trek series I would figured he was a kid when TOS first aired, not only saw it syndication decades later.
But that's neither here nor there. I re-watched Batman '89 recently myself and... Meh.
I remember having a much higher opinion of this movie when I was younger but on a re-watch it missed a certain "spark." Maybe the movie hadn't aged well, maybe the delicious taste of the Nolan films was still in my mouth and the horrible taste of the Schumacher films still in my throat or the usual tropes common to Burton anymore stood out more. (Though they weren't around as much in Batman as they'd later become.)
First of all, I agree with everyone above that the costume doesn't work. It's obviously very restrictive which just stands out. It's pretty much impossible for me to buy Michael Freaking Keaton as a badass crimefighter AND as a billionaire playboy hunk.
The movie does have good production values but as Warped said many scenes do feel claustrophobic like they were obviously done on a sound stage instead of outside and Nicholson's Joker is just absurd as also has been said it's not Nicholson playing The Joker it's Nicholson playing Jack Nicholson.