Put it to you this way, If Sergei can turn his life around, and become a team player, and untap his potential he would be a very effective top 6 winger. If not, when hes on he can be a speedy two-way player who can play great on the PK.
Unfortunately, Sergei is NOT that speedy. He has average NHL bottom-6 speed. This fault, more than mental faults or attitude, is what will forever keep his potential FAR below Patrick Kane's.