I think it doesn't make any sense to limit yet Wiggins' ceiling. Last time Wolves had 19 year old skinny rookie, he did put quite modest stats in his first year (10.4 pts, 6.3 rbs, 1.8 ast, 1.1 stl, 1.6 blk 52.2 TS% in 29 minutes per game) but still he turned to be quite OK pick later. :D
I mean that even if Wiggins doesn't seem to play that well in his first year, he has still a lot of time to develop later like Garnett did and turn out to be real two way super star.
So I say Wiggins ceiling is 6'9 more athletic version of Kevin Garnett with much better jump shot.