Not really. AP/CDR Alistar does what an AP carry can do with the addition of CC. The ones you play with (and every one I've seen except in high-elo replays) just suck ass.
Let's see...
Build: Tank items + Trinity Force + 8 (Aegis)
120 AD (base) + 30 AD (TF) + 8 AD (Aegis) + 90 AD (Ultimate) = 248 AD
Activate Ult: Get TF bonus + 90 AD
Attack someone: Deal 620 damage.
Hopefully get focused, because you're supposed to be a tank.
Pulverize: Get TF bonus, also deal 240 damage.
Attack someone: Deal 620 damage.
Headbutt: Get TF bonus, also deal 265 damage.
You should automatically attack the person you headbutted, instantly dealing another 620 damage.
???
2365 damage total, not including armor/MR, and not including trample, also assuming you were always hitting one target.
All of this and you can also take a beating, instead of just dying when you play AP.
I kill AD carries easily like this.
You can also activate E to give yourself TF bonus again, and hit them again. Another 620 damage.
All of this damage is from 2 items. One of them being a support/tank item.
Okay so let's look at an AP build.
325 AP:
Headbutt will deal: 265 + 227 + 120 + 325 = 937
Or with ult: 1027
"but chrono that's more damage!"
Except you're going to get killed and not be able to do much after that.
I've seen it happen every single time. Especially me vs them.
I can kill him.
My team can kill him.
I can kill them.
My team can kill their team.
His ultimate is NOT enough to tank alone.
197 Armor: Reducing 66% AD
w/ Ult: Reducing 90% AD
144 MR: Reducing 59% MD
w/ Ult: Reducing 88% MD
+3436 HP
+2365 Damage (not including any E+auto or trample)
+CC
+QS Sash (removes ALL debuffs, including ignite, morde Ult, crowd controls, etc)
vs
CC that dies.
I could understand maybe there was a chance that an AP Alistar did good BEFORE the two AP ratio nerfs.
He just doesn't deal enough damage to worry about building AP.
There are many other AP carries that have good crowd controls that can actually deal a ton of damage.
