That would just be horrible...

dont even compare the two, garens cooldowns on everything is much much longer

And more useful.

This idea is actually not that bad and I wouldn't mind it. The mana cost increases by 100 every time he ults. If he doesn't ult for 8 seconds or something, the mana cost is set back to normal. But he's nowhere near op, so if he got this change then he would need to get the rest of his kit buffed accordingly.

Lux's ult cd 24sec with 40% cdr. o noes a spam ult. plz nerf.

darius is weak enough, if anything i would reduce the cd on his ult.

Yeah and Garen also doesn't use mana, has infinite sustain, built in tenacity and damage reduction on his W, a form of hard cc, and is really tough to gank while having just as good damage throughout the game as Darius. So, you were saying?

Except he has a slow, pull, and movement speed buff all for landing thoses AAs, if you get one, getting a few more isn't hard unless they have the mobility of Jayce or Riven.

You realise that his mana pool is quite small to begin with. You basically want him to use no other skill for him to even attempt ulti chains (because you know using Decimate, Apprehend and Crippling Strike doesn't take mana). If you want the increasing mana cost on his ulti by 100 per use, then give him something to make his other skills viable. Say, all other moves have their mana costs halfed and are 50% more effective then what they are currently.

For someone who is supposed to be in the fray of melee combat, he lacks innate tankiness and/or sustain to get to the fray, and he lacks any form of true gap closer to actually give him the boost he needs to get into the fray. He has issues that the other bruisers lack. Leave his ulti, since it's the only thing that makes him decent to use.

All of which is avoided by simply clicking away from him.