It sounds like you may have been getting some bandwagon warriors. granted warrior dps is really awsome right now it should never be a warriors top priority. The only time a warrior should be tanking in deliverance is if the content is stupid easy, he is off tanking, the content is hard but the boss hits like a noodle, or they have asked/know the healers and they are ok with it. any other time the warrior should be in defiance. damage in defiance is much lower but you can still out put about 3/5ths of the damage you would in deliverance.

If its a pug group tank in defiance or pop a cd (thrill of battle+convalescence=defiance) to get that sweet triple fell cleave berserk combo off