First of all, in my opinion, Wiggins and Barnes aren't at all alike. I can't imagine why you think that's the money comparison.
Second, while Wiggins isn't as polished or as strong an offensive player as Jabari, he was a pretty good college offensive player. Here's an offensive statistical comparison of Wiggins and Jabari:
Code:
Stat AW JP
---- --- ---
PPG 17.1 19.1
points per 40 20.8 25.0
Usage 25.4 31.7
oRating 112.3 111.5
eFG% 49.8% 51.1%
true shooting % 56.3% 55.8%
assist % 9.1 8.6
PER 21.4 28.4
win shares per 40 .170 .205
OR% 12.3 11.3
Yeah, Jabari has the advantage, but it's not as big an advantage as you might think, meaning Wiggins was no slouch on offense. And Jabari was generally considered to be one of the best two offensive players in college this season, so it's not so much of a black mark against Wiggins that he's not quite as good an offensive player as Jabari.
Interestingly, one of Jabari's biggest advantages over Wiggins is Jabari is a much better
defensive rebounder, with a 23.0 DR%, versus Wiggins's 14.1 DR%. Not sure how well that will translate to the NBA, but you never know.