I understand that part, and that sounds fine and all, but you have to look at it from the outside and not from how Darius players see it.
Giving him a huge slow like that makes it very convenient for him. How do you lane melee top against him with that slow? You cant. You simply cannot. The fact that Darius needs to "Walk up to you" is the same as any other melee champion. But why is it that Darius get sthis huge slow? Despite it being obvious that he already deals huge dmg, true dmg and a one shotting ultimate.
I'm not saying get rid of the slow, I'm saying cut that shit to downright manageable because right now it isn't. And even if you can still walk away from him his Q range and pull still in range to get you. There is literally no escaping him unless you stun and then remove the slow with an item then flash out of his range. otherwise you just stay away the entire lane phase. Which isn't fair at all, he still gets to poke you under tower with the Q, and then just dive you and dunk you.
I understand his lateg ame bad, but his early game not manageable at all. Unless of course you play champions you do not want to play in order to counter him, else if you main melee champions its just a bad game.
Does this not make sense?