He ages like a damn vampire.

I think he could play late 40's Batman pretty well and I still think he'd give an extremely compelling portrayal of both sides of the Bruce/Batman coin, as would Damon.

Between Brolin and Gosling, I'd say Josh brings a more physical presence. He likely brings a square-jawed, straight forward Batman to the table with Superman the fold whereas Gos will most likely swag all over Supes.

I still would like to see Clooney given a second shot at Batman.

All that said, Affleck is still the absolute best man out there for this job, but I'd want him to write and direct as well as play Bruce/Bats, and none of that is in the cards.