My main problem with the warhorn is the damage and the long cooldowns. The abilities themselves are nifty in a way, but the recharge time is far too high to make it worthwhile. And the damage definatly becomes lackluster, as your taking points out of dps and putting them into support. I myself am a 5 signet greatsword warrior, and theres a reason why its done so much. Its godkittenoverpowered. More crits than the eye can see, and it even has a charge like the warhorn does. So i would maybe justify a warhorn in PvE dungeons, where buffs and boons win the game, but PvP, i think the damage output is far too low, and usually theyll be so many boons going around your buffs wont even be that needed. Just my thoughts.