He's a great dribbler, clever passer/crosser and is incredibly 2 footed.
Off the ball movement we'll see. Wouldn't shock me if it's a problem early. Also, positionally, I'm not certain he'll end up filling Neymar's spot. I could see them ending up with Messi central and Dembele popping up on both wings or even Suarez in Villa's old left-striker position with Messi as the false 9 and Dembele wide right.
But I do think it will work, even if it takes a month or even to next season to really flourish. Kid's got great talent and is a naturally complimentary attacking player now paired with 2 incredible goalscorers.
Barca's midfield is still a massive issue, though. I'm a big Busquets fan but he really seems like he might having a genuine dip many players at his level never get, but like Giggs had for us at a similar age. Paulinho might give them energy in the CL or a tough game or two in La Liga, but is he going to be technically up to it? Rakitic seems to have hit a wall. Iniesta's aging means he should really be on the older Giggs schedule, presumably either playing once a week or being an impact sub.
Their fans might have a conniption but I wonder if they play a big game this season with Mascherano and Busquets in front of their defence to shore things up. Maybe against Real Madrid if they roast them again in the next Classico.