I'd say Mackinnon and RNH have brought some luster back to them after a year or two that were below expectations. Draisaitl is looking really good without Hall, which was a serious question going forward. I'd say Matt Duchene and Schefiele have raised their stock in my eyes.
Gaudreau has looked amazing, and has probably raised his stock in some peoples eyes, but not mine as I already had a high level of respect for his game. Halak's played well, but any goalie performance in a short tourny I'll take with a grain of salt.
Matthews hasn't really raised his stock in my eyes, but has exceeded my expectations and confirmed my belief in him.