So Darius is actually a lot stronger than his winrate lets on

http://champion.gg/champion/Darius

It all comes down to which ability people max second. Maxing E second is much stronger since W doesn't gain much from leveling up while E gains armor penetration and a much lower cooldown.

E max Darius has roughly a 62% winrate in plat+, over about 1600 games which is not a small sample size.

That said, W max Darius has just over a 52% winrate, a full ten percentage points lower than E max, and people max W second more than three times as often.

While I doubt that his winrate would stay at 62% if everyone maxed E second, I think it's pretty fair to say that he'd be in the 58%+ winrate range if people were actually playing him correctly.