So did did Renekton just become useless over the last patches?

Ok I just played Renekton into Darius and I got wrecked. Yeah the other player was probably a little bit better than me but not by much. So I used to have a really easy matchup with Renekton against Darius. You wittle him down with Q in lane and push him a bit around early game. If you don't play stupid aggressive you had a little advantage in lane. Yeah Darius outscales you by mid-late game but there is a phase where you have the upper hand. Did this just vanish?
Darius heal destroys this completely. You have to stay out of range of his Q because the damage and heal instantly take away your advantage. If you try to stay inside his circle so that he doesn't heal Darius just happily autoattacks you, resets and slows you with crippling strike and lets his passive Hemorrhage do all the work. So you lose early autoattack wars and that's ok. That's what makes Darius Darius. So if you stay to close to him you lose the trade due to passive and if you stay at range he either zones you with the range on his Q or you're forced to fall back on to the highly predictable "Renekton-combo". It's the standard E onto him, stun him with W, use the burst from Q (preferably empowered) and get out with the second E. This is what used to make Renekton so safe. However if you're forced to this combo you will never get your rage going since he already zoned you out of rage generation (minions) and your damage is neglectible and every Darius player who knows what he's doing will hit you with Q after it. Sure you can try to e-w-q-e and get away before he hits you with his Q. However then you're bound to the long CD of E (18 sec) and if you walk up to the minions he will Q you and there is nothing you can do to stop it (well yeah you can stay back, but that's him zoning you).
So what is left? You can try to outsustain him, but his sustain is comparable or better than yours. So the heals are pretty much comparable but a-haa! then you bring up the argument of Renekton having no mana whereas Darius uses Mana. So if you spam your Q and Darius spams his Q surely he will run out of mana at some point?
I want you to go and look at Darius Q mana cost. It starts at 30 mana and goes up to 50 mana at level 5. Yep, Darius never runs out of mana if he's using Q and if he ever so slightly faces some problems a single pot negates this.
What about level 6 the point where Renekton is supposed to be super strong? Well Renekton is designed to to harass you and then at level 6 when you wittled your opponent down enough to get him in kill range the extra health and magic damage give you the stats to overpower your opponent. You won't be 100% HP either but the extra HP gives you an edge. Darius doesn't care he will ult you negating 50% of the bonus HP you get without having a Hemorrhage stack on you. And we all know not a single Darius ults you while you have no stacks unless he panicks or gets in a tight situation. 2 stacks of Hemorrhage already deals the same or more(if he has AD runes) damage per second than your ult. Renektons ult is designed to not be able to burst the opponent, so he has time to fight back. What this amounts to is that on the surface it looks promising for Renekton but at best you can fight on equal footing due to hemorrhage and the burst of Darius R negating your bonus HP. And then Darius simply outscales you.

So yeah. I'm not saying "Riot pls nerf Darius so broken" but I have the feeling that something is very wrong here. When THE designated early game lane bully fighter tank gets pushed around early game by a Juggernaut late game champ something can't be right. Granted I have difficulties against all the Juggernauts but I can play around even Garen with Renekton.
I don't know if Renekton is now undertuned or Darius overtuned but I actually think Renekton is more or less fine balancewise. i just can't wrap my head around the turning upside down of this matchup.