i was thinking about a traited tank stance as well. but without the damage penalty since atm endgame is done mostly out of tank stance anyway. If SE thinks damage is too high they could always adjust potencies. for WAR just give them access to all their skills all the time (same for BP on DRK)
Sword oath and darkside should be traited as well.

and to not make it boring tanks could be given a mechanic which lowers incoming damage by performing in a certain way. right now tank stances are mostly a thing to discuss on the forums but by far not an interesting game mechanic