It's amazing how fast this guy develops, a lot areas of concern from a year ago have been addressed. Pointed this out a couple years ago just from gauging his interviews and how much he "restrained" himself those first 20 games as a rookie in order to earn Cooper's trust, you can just tell that he's a smart, coach-able player. Him and Drouin actually have a lot in common, they're both flashy and prone to dumb mistakes but their biggest difference is how they learn from it. Drouin will repeat the same thing over and over while Sergachev adjusts.
To me, his 2 biggest weaknesses were his lackluster and passive board play which is now probably one of the strongest areas of his game and something that took Hedman 5 years to develop. The other was the urgency coming out of his own zone with the puck, guy would get pick-pocketed regularly because he was so casual coming up, watch him closely now - he takes a quick steps coming out from behind the net then looks for a play.
I think the biggest thing for him to develop now is to be more assertive in the offensive zone and take control, he should be quarterbacking plays not defaulting to the star forwards - especially Kucherov.