Lower cooldowns can quickly get to a place where that does mean more damage, especially with Trample.
As for AP builds - Alistar had a few appearances in the current tournament scene as Triforce + Shiv top. AP isn't the only way to go mad cow. The Yolo Cow is real.
Generally speaking I like the Sunfire + Chalice bovine, and mostly rely on his +90 AD steroid to beat things into submission while being impossible to kill, and just spamming heals to get tramples off or generally just offer moral support when in the middle of a siege.
As far as killer bull builds go though - the reason that works isn't his damage potential. It's the 70% damage reduction he gets to give 0 bothers about taking damage. Mostly an AP ratio skill and Lich Bane is what provides his AP build damage, which is much more Lich Bane's fault than the minotaur's. Lich Bane almost makes AP Garen seem like a good idea, you just need 1 solid AP ratio to pull it off.
The big reason I'd say most players trend towards damage with Alistar is his 0.01 cm radius on Pulverize though. Alistar's 90 AD steroid isn't small and he's got enough AP ratios to make Lich Bane work pretty close to where it needs to.
Played as a tank though, the big advantage you bring is mostly CC. Which pulverize has consistency issues with, and Headbutt can go horribly wrong on. Generally speaking you need to use Flash for the game-winning Pulverize Headbutt combo's as well, where most tanks tend more towards the Malphite style of press R, deliver tank to location, stun all enemies around tank, QWE are now available.
Granted - unlike Skarner and Galio you can just headbutt the enemy tank out of a fight for gap-closing on the enemy team and then proceed to Pulverize everything nearby. Much style points when that ends well. I'd just go more for his CC being a little easier to use if you want to encourage armor cow. He doesn't reeealy need lower cooldowns, as his abilities, when used well, are all pretty strong.
