Full Ap chogath can do 1000 true damage to an enemy.

...1000 true damage? Ha, that's nothing considering you have to literally be standing next to him to get hit by it. Meanwhile, Fiddle, Kat, MF, and Lucian have around 300% ap scaling on their ults. That's around 2700 magic damage to multiple enemies at long range, or 900 damage assuming enemies have 200 mr or something. I don't see you complaining about that, so Cho's scalings are scary, but not overpowered.

It's balanced because in order to go "full AP" Cho'Gath tends to sacrifice some tankiness. Getting hat instead of damage resistance is a risk that only makes sense for Cho when he's already ahead in experience, and his base stats are high enough to compensate for not buying armor or magic res.

Full AP Cho has a lot of magic and true damage, but anyone who can dodge his Rupture can kite him for days. And he simply doesn't have the defensive stats to withstand a dedicated attack by two or more opponents (or a Vayne).

Cho'gath's abilities, in general, are hard to get off without someone else helping. That's why they have such high ratios... although I kind of think Cho's ult shouldn't be true damage against champs... but that's just because I think true damage should be supplemental, not core.

as darius you don't even need to go full ad to get 1k true damage :>