Dahlin's most egregious mistakes almost always happen when he's either playing his off-hand side (which I usually dismiss because he's out of position) or when he's overly aggressive on the opponent's blue line (his fight or flight instincts need to improve here).
Honestly, neither of those bother me all that much. My biggest frustration with Dahlin is that he has not yet figured out how to translate his skill into how to control a game. Guys that he is routinely compared to like Karlsson can look like a tire fire in their own own for long stretches, but then they completely take over the game for a period or two on route to a 3 or 4 point night. Dahlin on the other hand will walk the blueline brilliantly, completely deke two opponents, and then when he's created that time and space for himself he'll pass up an open lane to the net or drop it back to the point easing the pressure on the opponent. There's also his patented curl and drag shot from the high slot, which I thought would have improved moreso than it has by now. He really hasn't figured out out how to really put the pedal to floor yet.
I'm hoping that as the skill around him improves his play will also imrpove. I knowe that's an odd thign to say, but after all what good is a great outlet pass if your forward can't do anything with it.
I think eventually he puts it together, but I really think he needs a vet that can play in his own end and clear the net lined up next to him. Manson has been my dream target for years, but admittedly I haven't watched him at all this year to know if he's still holding up. Still, having that calming vet presence next to you can really open up your game. We saw a little bit of that when he was paired with Pysyk, but it would be nice if he was next to someone that wasn't a 3rd pairing dman.