Kevin Smith -- Ben a While Since I Talked to My Batman Buddy, Affleck (VIDEO)

Kevin Smith and Ben Affleck used to be tight -- ya might even say like Batman and Robin -- but something's changed.

We got Kevin out in NYC and, naturally, we hopped on 2 of his fave topics -- Batman and Ben. Then came the shocker about how long it's been since they bro'd down.

Check out the vid ... Kevin also dropped a few suggestions for who could be the NEXT Batman. He wasn't taking a shot at the current one.