There's one thing that I've really though would help BF, but it would probably very tedious and is definitely SFX-heavy. Take out all the neon stuff. The lights waving around everywhere at the end are annoying, but even before that, there's a ton of stuff. I haven't seen the movie in a while, but there's some stuff (like the...neon spray paint on the walls of Gotham' slummy areas) that sticks out really badly. I realize that it would probably be too extensive, but it's surely a thought--and maybe someone out there reading who has a lot of experience in that kind of digital effects work and a load of freetime could give it a shot?
But again, no matter what, kudos on the cool idea, man!