Does Darius' spammable ult seriously do more damage than Garen's or Cho'Gath's with no downside such as having a two minute cooldown or requiring feast stacks? Seriously Riot, you may as well just start selling power if this is the way you are going to design champs. Also, you can fire your balance team, because they clearly aren't doing anything.

Darius is pretty good at pubstomping.

Cho'gath offers CC, silence..

Garen offers get out of free slows, spin to win, defence steroid..

Darius offers damage

Darius is strong. Darius isn't OP.

see, the thing about darius's "spammable" ult is that it requires a few things that end up being detrimental to your team:

1) he has to get lots of hemorrhage stacks before he can deal his full damage with it.
2) he has to stick to his target to apply those hemorrhage stacks.
3) he has to steal the kills to "spam" the spell.

What does a fed darius do? Get more kills, and starve his teammates. The stronger darius gets, the stronger his team isn't. It begins to have a negative effect on it, and his ability to take all the kills for himself begins to suffer since his teammate's damage is also suffering.

Cho'Gath has a tremendous amount of CC, utility, is an extremely powerful jungler, a monstrous(no pun intended) health boost, high base run speed and his Feast scales directly from AP, and does increased damage to minions.

Garen has high mobility, inherent tankiness, sustained AoE and a silence - and while he is a weaker champion than Cho'Gath, he still has strengths.

Darius has a short range grip, armor penetration, an AoE and a slow... and his ult which requires him to hit you 3 times with auto attacks to do any real damage. He has a very slow base movement speed, and very little utility. He is very easy to kite.

Darius was picked 6% of the time, banned 6% of the time and had a 0% win rate in recent tournaments. He is far from a tournament viable champion. By your argument's logic, Nasus would be nearly 4 times as powerful as Darius which is obviously not true. Darius is a champion whose inherent, intentional strengths are accounted for by designed weaknesses.

In fact, his quote, "Exploit every weakness" sums it up quite well: kite him, harass him, and don't let him run top lane. He will be useless compared to many top lane champions mid game, and late game teamfights are typically decided too quickly for him to be of any real consequence.