Get that agility if you don't have anything significantly better.
Currently there's a necklace and a ring available. Especially the latter is easy to get as you ought to be exalted with just about anything given the tabards in the game.
Equip that ring. Watch your dodge jumping through the roof.
Learn to love jewelery with mastery and agility.
Edit: MMO Champion released the latest patch notes earlier today. Seems agility will no longer convert into dodge rating for us plate tanks come patch 4.2.