I love the tenacity and edge he plays with, especially as a 17 year old "Russian" kid. He engages in physical battles and doesn't why away from contact. His stride needs some work. I see what you're talking about where he looks like a headless chicken at times.
A more skilled Hagelin, imo, can translate into a top-line forechecking monster.
Shame he wants to spend more time in Russia and continue his development. It's probably best though. I prefer the guy we select isn't 3 years away from coming to NA.