You build attack speed because it reduces the cooldown of your heal, which is why he has so much 1v1 capability. His AP scaling is such that you'll do more damage if you build damage rather than AP with the attack speed.

I tend to agree with the other poster, but not quite as harshly. I'm not sure AD is where you want to be with Taric.

Why not have a final build of something like:

Frozen Heart // Nashor's Tooth // Manamune // Blade of the Ruined King // Trinity Force // Boots or Zephyr

Sure, you still end up with a little bit of AD because of BotRK and Trinity Force, but it's a minimal amount, and we're building the items for their other abilities anyway.

Also, For runes, I was thinking something like Magic Resist/lvl blues, Armor yellows, Attack Speed reds and Movement Speed quints. With Movement Speed quints and Zephyr you could probably skip the boots altogether.

Just my two cents, but I think this might be a stronger build direction

This guide is ******ed. Taric don't have a single ability that scales with AD and he is melee with no attack speed steriod. Why would you build AD Taric?