Seems good,but yeah definately swapping out the 3rd/5th lock for a tank,post 60 and 70 proper warrior/palas tank.
I was tempted to go holy too but i found healing more than fine,(and i also wanted shadowform ;p)
Wondering if a palas and 2 holy priest might not be better for running OL instances tho,with a reskill for higher dps on the locks,post 65
(Another thing i have setup is a bind to double bubble both lock pets before they dash in).