I think the part that makes feel so overwhealming at times, is the fact he gets free speed buff on blood stacks, so if he managed to hit you once, you pretty much can't get away unless you're a high mobility set up. And the grab, I don't think its super long range, but at least increase the animation of the axe to cover the whole grab, nothing more annoying then not only Darius being so fast, when the axe is clearly behind me I still get grabbed.
I mean damage wise, there are other champions that put out the hurt just as good and better then Darius.
Quick Silver Sash can remove his blood stacks, which if he tries to ult you at 900 hp instead of 300 where it doesn't matter he could have Q'd you anyways but felt like R made him more of a man, can save you and waste his ult.
I guess i'd stop hating darius so much if they fixed his E's animation to cover the grab, so it doesn't feel like i'm being pulled back when it clearly missed. And of course does he really deserve speed buff and a bleed? (I have no problem with him having a bleed) At least require him to build phage before he's allowed to run you down?. Past that i'm not sure what could be nerfed on him with out making him under powered.
I think people are looking at the wrong aspects of Darius when they complain about him. His grab is nearly auto attack range for many champions. And free speed/ slow combined with his armor pen.
But to be fair there are other champions which are far harder to keep off of you, like Katrina, but unlike some one like Kat, Darius can't just jump away if he needs to. Darius doesn't have escapes, (though usually he's not the one that needs escaping) but if he does, he can't minus flash. He has to commit himself to the fight alot more so then many champions.
While it never feels good when a darius does well, because you know they are playing darius because they think he's OP, and he becomes very overwhelming if some one feeds him, truth is many solo laners can have the same said about them. If they get fed they can have a huge impact on the game, if they don't they won't be such a big issue. An unfed darius is a squishy darius, sure he can pull you to him, but it'll probably get himself killed for doing it.
I'm not sure what points I overly wanted to make on this, because I'm not sure how i feel about the champion as a whole. I don't think he's over powered entirely, but there are some minor tweaks at least visually (dying because you got hit by an attack that clearly missed is just sloppy design) that wouldn't make him feel so BS at times. I feel if they really did nerf him, it would be hard to not over nerf him.