Kha Zix ult
Now this whole thing will be a moot point if it's too difficult, but how about for an evolved ult, it checks for the stat you are stacking the most, and changes function appropriately?
If armour/MR was being stacked the most could give damage reduction on auto attacks/spells respectively Maybe for AD it reduces the isolation range health changes W heal to a % of his HP per enemy champ hit?
Obviously everything could be screwed around with, but you get the idea, would hopefully fulfil more of the "adapt" part as he has something about him he can change according to his environment, rather than himself.