I think it's too early to tell. Wiggins has the same potential as Smart does on defense and should be able to reach Green's level on offense - that's a very good player right there.
After last year, people were saying Shabazz Muhammad was a total bust, but he is scoring 13 ppg and has really been tearing it up lately (including last night). He obviously doesn't have the ceiling that Wiggins has, but it often takes at least one year for a player to get used to the NBA. Wiggins was thought to be a bit timid coming out of college, so none of this should come as a surprise.
As for the Wiggins/Bennett versus Smart/KO debate, I probably would go with Smart and KO, but more because I think KO is considerably better than Bennett.