MeanJoePhaser just scratches the surface.
Let's just put it this way:
60's Batman is dumb but campy in a self-aware way. They knew what they were doing was silly and were ok with that. It's a perfect for what it was trying to be.
'Forever' took all the dumb stuff from Adam West's show, ignored the self-aware ironic tone, and basically tried to make it feel important and 'real.'
It had no idea what it wanted to be and as a result does no one thing well. As one simple example, Tommy Lee Jones is a great choice for a serious Two-Face. But they wanted a goofy Two-Face. Jones is the exact WRONG choice for that role! It's like they changed the script after casting or something! The whole movie is like that...taking things that could be great and doing them exactly wrong.
The ONLY reason people give it any credit is because the one that followed was somehow worse. Hardly a stunning endorsement.
it's just as good to me now as it was when I was ten.
Well there's your problem. Remember this: What you liked at 10 is never a good thing.
This is true for everyone, and we never quite outgrow it.
It's why I still love Mr. Bean
but I'm not going to try and defend myself there.