Youre aaaalmost onto something but a little misinformed.
Defense skill does nothing for crushing blows. Imp shield block pushes them off the table but only as long as youre not attacked more than twice in 5 seconds.
Full prot increases threat gen through defiance, imp sunder, 1h weap spec, imp blood rage and shield slam which is the best snap aggro available atm. You can maybe generate better aoe threat with a 2her using sweeping and dancing to whirlwind, but itd be pretty marginal.
That said, I leveled as arms/fury because leveling prot is for masochists