They say 'high skill cap champs should have lower win rates'.
Then there is something seriously wrong with 
He has a >50% win rate in all ELOs and 53-54% in Plat+. Its not like he has a negligible playrate either. He's been in 4/5 of my games today and the one he wasn't in he was banned.
Considering Draven is supposedly one of the higher skillcap champs in the game, something seems very off. His level 1 damage coupled with the rate at which he snowballs are out of control. Addressing that would be my suggestion.
######Note: Hyperbole
nerfs are going to help him
lot of assassin nerfs and survivability buffs helped him
are probably the most difficult ADCs.