Demar Derozan does seem like a reasonable comp for him, but I think his defensive potential is a lot higher than that. Derozan's offense with better outside shooting and elite defense would make Wiggins a star.
I agree with others, it's an early season slump. That Wolves team, like many young teams, is a mess of guys trying to figure out their place in the league, so it's not super surprising that a guy like Wiggins, who doesn't always have the ball in his hands -- might struggle. Especially with Karl Towns playing really well early.
One of the biggest knocks on Wiggins has always been that mentally he's a little bit too much like Jeff Green -- prone to disengaging and drifting.
I wouldn't worry about it too much if I were a Wolves fan, though I think I'd pay close attention to what the veterans on the team i.e. Andre Miller, Tayshaun Prince, and Kevin Garnett were saying about Wiggins. Those guys know what it takes to be very good / great in this league.