Kucherov is probably the favorite, but Vas has a case for the same team in terms of most valuable.
The problem is the guy that wins the Art Ross (exception is sometimes the Rocket) is the clear favorite for the Hart.....so it would be Kucherov if it the vote ended today.
But in terms of impact, I think Bergeron, Malkin, Kucherov would be my top 3.