I left my Warrior who recently dinged 70 on full protection tank-spec. And to my surprise, doing the left-over quests at 70 is fun.
First of all, yes it is slow as your dps sucks. But when you do it consequently, wearing your tank gear and at all times use shield block vs melee and shield bash/reflect vs casters then you are basically invincible. I just found myself fighting 4 even-level mobs with ease, coming out with 50% HP, 2 lvl71 mobs i can also handle fine. Fights take long, but i always win.
An additional advantage is that i do not need to respec for tanking this way. I can just quest and whenever a group needs a tank i am immedeatly ready to go. Even did some PvP dailies in my tank-gear and spec - just looked out for a horde healer and sticked at him like glue...shield bash, Stun, shield slam.....he shouts for help....i spellreflect the CC....melee comes to his help...i laugh while they need ages to melee me down in full tank gear, all the time stopping all heals from the healer
