Have you ever been able to avoid giving Darius his heal and bleed from his Q by standing next to him? In principle its a possible counterplay but in reality it almost never comes up since its so easy for him to maneuver you outside of the dead zone. It really feels like the fundamental flaw in his design.
Some champions like 
are probably even too large to even stand inside his Q in the first place.
What are you suggesting?
It's less, has it been dodged? and more, have you ever missed with it?
It forces Darius to do a little more thinking than a-move and gives full-frontal melee like Garen an opportunity to be near him and not sad.
If it went up to full damage but didn't heal, even, people probably wouldn't notice all that much. It's the heal on the outer circle that's important.
You could easily dodge inside it with clutch timing, but it's really more of a point on Darius' end; he can't, for instance, just stick on you with basics and spam it (since it does end on a short cooldown). It forces him to be engaged with the fight and encourages smart play over hard play.
I do feel that they could make the radius in the inner area a little bigger. It is really hard to not get hit by the healing part when going in on Darius.
