He's going to have growing pains..he's a high risk player, Subban and Markov still have shockingly bad games due to their playing style and the former is one of the best blueliners in the game.
I think he has shown he is worth putting up with the bad though, it would be a mistake to be trigger-shy with his usage.
He makes some really intelligent reads sometimes on the ice. At some point last game, Pacioretty came down low to recuperate a puck, but decided to chip it off the boards. I don't know who the hell Pacioretty was expecting to get that chip off the boards, since he's the winger and he should be the outlet option on a play like that. Fortunately for Patches though, Beaulieu exploded from the front of the net to get to that puck before the defenseman and we managed to get out of the zone.
The guy really has a good natural and instinctive feel about what to do and where to be on the ice. That combined to his skills and skating ability will enable him to outweigh his bad plays with many more good plays in general IMO.