There are certainly drills and techniques that can help improve footwork, but you are correct. It's unlikely he becomes a quick, pulling type guard, at least as a steady diet.Yeah, his body composition isn't an issue, he actually has a really solid build for a guard, not sloppy. I'd prefer the guards to have a thicker lower body, but he doesn't have "thin leg syndrome".
His issue is lateral movement, I don't know how much anyone can improve in that area, that is sort of a natural thing athlete have, but he seems like a player that will take the coaching and work on his issues and that is all anyone can ask at this point.
It shouldn't be detrimental in downblocks, and traps, at all. Pass sets is the area that needs some work. Again, it's hard to complain a lot, given the revolving door of guys he has had to play with. Not that he's any better than they are, but cohesiveness as a unit is important, and he is just a rookie. The NFL game happens faster than at Wisconsin.