Revere's walk% by year:
6.01
7.21
7.73
7.79
5.41 (5.77 in MLB)
4.15 (4.23 in MLB)
Overall he's at 6.29% career, and trending downward as he moves into the majors. AS Pig said, it isn't unheard of for a guy to figure it out, but he's at 2500 PAs as a professional, and he's not getting better in that department, he's getting worse. Hackers tend to stay hackers (See: Young, Delmon) but most of them are guys who can give the ball a ride once in a while and aren't just praying that another grounder finds a hole every time they're at the plate.
I hope Revere succeeds because it helps the Twins, but I'm still hoping that they can eventually (and sooner than later) piece together an outfield with guys whose entire offensive game isn't predicated on flurries of singles and nothing else. That said, I'm nowhere near delusional enough to believe things like "Revere could have a chance to be an All-Star every year", which are just flat-out idiotic. The guy is a nice piece, but if he's anywhere near the Twins' best player in any given year, that will be a historically terrible Twins team.