Cho'gath Should Keep Growing After 10 Stacks
Currently, Cho'gath does not increase in size after 10 stacks for balancing purposes. It makes sense, because if he linearly continues growing at the same rate, a super fed Cho'gath may be able to take up an entire lane in a teamfight. However, when you hit ten stacks, the pride and accomplishment of growing and watching yourself slowly get bigger and bigger ends and you're stuck with that size forever, even if you manage to get many over ten stacks.
To solve this, we can use a soft cap (also known as diminishing returns) to still have control over Cho'gath's size while also letting him as an infinitely growing beast. The blue line in the Desmos link is how Cho'gath's size growth acts currently. The dotted blue line is if we remove the hard cap and implement a soft cap instead. As you can see, his size growth slows down very quickly, but still enables him to still infinitely grow and preserves the satisfaction of watching yourself grow bigger as you gain more stacks.
The way the dotted line is designed is so when you go from 9 to 10 stack uncapped size, you would just need 1 stack just like normal. To go from 10 to 11 stack uncapped size you would need 2 more stacks (12). To go from 11 to 12 stack uncapped size you would need 3 more stacks (15). To go from 12 to 13 stack uncapped size, you would need 4 more stacks (19).
It becomes very hard to grow super big, to be as big as 16 stacks without a soft cap you would need 37 stacks with a soft cap (that's 21 more stacks than uncapped!). Also if a Cho'gath actually manages to get 37 stacks in any game somehow (really hard), he deserves to show it by being at least 6 uncapped stacks bigger than a 10 stack cho'gath. It would be so satisfying and super fun to manage to see how big you can get in a game!
I'm not sure how much of a gameplay (dis)advantage infinite growth is (you get hit by more skillshots, but we all know the bigger the better) Thus I have two other harsher diminishing curves in the demos link that I made which still let Cho'gath infinitely grow but they are a lot slower and may not be as noticeable. You can enable them by clicking the blank circle to the left of the fourth and fifth lines.
Let me know what you guys think.