Alistar Rework Maybe?
Just saying: -Q + W combo is so game-makingly powerful and has been made so consistent to pull off that other aspects of Alistar have had to be nerfed to preserve it, to the detriment of Alistar's original defensive identity and ultimately making him a lesser Malphite ult and heal bot.
-Aforementioned combo requires no aim or display of skill beyond timing, made near-irrelevant due to making it so Pulverize could be buffered while activating Headbutt.
-Full AP Alistar is an absolute and total gimmick, but with his base damages and ratios can literally- as in I am not exaggerating, this is actual fact, from personal experience- take someone from 100% to 0% without giving them any opportunity to respond or outplay. And if his combo doesn't kill someone with raw damage, the sheer amount of CC makes them easy to sweep up for allies. And because of his ult, Full AP Alistar remains incredibly tanky and can't be focused down like a typical damage threat.
-Pulverize's stun feels incredibly bad and clunky to play against because it comes immediately after the knockup, leaving players wondering why they can't move. I know Pulverize comes with a stun, and even then after getting hit it felt like the game wasn't being responsive rather than "I am stunned".
Yes, there are champions who need it way more. But Riot has multiple ChampUp teams, and have on prior occasions done smaller-scale reworks interspersed between the massive ones. Honestly, I think Alistar could use one of those to make him less painful to play against, and more interesting to play as.
Just my two cents. I'll get my scuba gear for the downvotes into the seabed.