in all my days tanking has never been to much of a hassle
i hit 1 to sunder, a timer tells me when they expire so i can re apply before i lose all 5
(saves me from blowing a mercy point in devastate)
hit q to shield slam (when the cooldown timer tells me its up)
and hit revenge (2) when the warning tells me to
other than that im right clicking to use heroic strike until q or 2 is back up,
bloodrage is e for whens its up, and taunt is r
stances are f g and h respectively, tanked all of kara with my left hand
except for taunting i suppose
one more thing, intervene is better than you think, a nice macro is intervene immediately following /assist %t
you'll find that in most mt interfaces