Taric brings unparalleled burst to the bottom lane. That's a fact. A quick E-R-W combo can halve a carry's life early on, and opens up your carry to jump on them, with immense buffs and debuffs applied to the enemy carry. Combine that with being a tankier support able to take a good amount of beatings, and having a very nice heal, and you've got a recipe for OP. An aggressive Taric- based bot lane can snowball very easily, and combined with a high burst carry like Corki, Tristana, or Graves is damn near an easy win. While he still doesn't have nearly as bad of an imbalance at bot as Blitzcrank, he still may need some tweaking to prevent an aggressive Taric from ruling bot lane.