Alistar is a (tank) trash support

Alistar is by in large a bad support. His success and win rate might differ across Elo's from low to high, but in mine, I consider him to be one of the worst. Let's take a look at some of his problems.

He's too item dependent: This statement alone sets him far apart from other supports. Why? They aren't supposed to be! Support champions are those that make up their lack of gold with high scaling but lower than average ratios( Annie for example ). This is also why they're supposed to fall off during the transition from mid to late game. What's the point of having a tank support, that can't actually tank until the laning phase is almost over! Aren't they supposed to support their ADC to the best of their abilities?

High Insane Mana Costs: Alistar also gets the short end of the stick for being classified as a vanguard instead of a mage. This means he will always have a disproportionate cost on all his abilities compared to mages such as Soraka / Sona.

A useless passive: I have never seen a more useless passive given to anyone except Sion. It reads, after 7 minions deaths, Alistar roars healing his allies for 20 - 139 health? I repeat, 20 - 139 health! What is this Shrek? You could get more value in health potions if you bothered to work on your horrible CS skills ADC mains.

In short, unless your gold and above, don't play Alistar. Every time he was on my team or the enemy team, he would always perform poorly.