I feel that unless warrior gets a parry-driven proc, it will lag behind any changes made to paladin or dark knight in the MT role.
As an out of the ballpark idea to go along with warrior getting a parry driven proc (say, a minor bubble like the original storm's eye that could be proc'd after parry), that parrying effects also have a change to activate after auto-attack based on the parry rate (i.e. 50% of parry rate = activation rate).