A Warrior (or Paladin for that matter) using a PvP shield in the PvE world is hardly something new.
In BC some of the best shields regarding EH came from PvP (at least to my knowledge).
That said, with EH pretty king in ICC and threat such as it is (will probably get an increase in threat with the new weapons actually...), I see no real reason you couldn't get them to tank with.
"Upon an order we plead, with the lure of a song, a sacred song, to the moon and the stars. An illusionary light is here placed."