It's getting very stupid when you have champs who don't need to skill shot their ult and nuke for like 1300 hp just instantly ending team fights.
Can't do anything even as tank. There's not enough Mres to stop these nukes. And if you dominantly build Mres their AD is just wrecking you.
The mana gain is unique I know this, but make it non-stackable.

I assume that your talking about Karthus, and thats a lot of farm he has to get to have that much damage, the best and to easiest way I find to beat Karthus is not let him farm, kill him, and win the lane, or have jungle gank often. The AAs needed for that much damage is close to 20k thats a lot of cs, plus Banhees and Hexdrinker are always a thing.

Well no not just Karthus. I've seen/done on others and it's pretty much just insta kill or insta-gib

If they're stacking Archangel's Staves, they are literally glass cannons. Two Negatron Cloaks are enough to live long enough to kill them.

The only carry I've seen who can freely get away with stacking Archangel's Staves is Kog'Maw, and that's reliant on a team who can protect him. The current meta also doesn't allow that style of Kog'Maw very often anymore.

True but it goes back to what I said thats a lot of cs, and Banshees and Hexdrinker do wonders. Plus most of those other champs are single target nukes, and channels. Another and big thing is CC, yes people say this often but its true, many times its not used wisely. A lot of people don't know but CC effects reset, for example if someone is suppressed then stunned the suppression no longer applies, though the damage still does.

o.-