He will never be a gifted offensive player. He won't be able to post up or put the ball on the floor or hit 15-20 footers at a rate to approach high usage potential. However, I do think that he can become a possible all star player. He has the potential to be an elite rebounder/shot blocker that can score 10-15 garbage points with a jump shot or two a game.
I like the Ben Wallace comparison, mainly due to his size. A little more offensive game though, won't get to Wallace's defensive level.