Actor and martial artists Scott Adkins auditioned for the role in BvS before Affleck was casted. This is his audition tape.
https://youtu.be/ynbnSykhV8I
I like him and would be an interesting choice but personally I see him being more of a cbm villain than a big name hero. Dead Shot or Deathstroke fits him more
if you’re a good actor as well as martial artist than you can be batman, acting is always the most important though
He could pull it off but I think he could do a better performance as one of those two villain characters.
I hope he auditions again though