So far I must say this skill is surprisingly useful. When I find myself in dire situation, stomp is usually way to go... when enemy armor is down. Since enemies have tons of it from midgame on, it's not that easy to use.
Friendly fire as way to balancing it doesn't seem that bad. Reminds me of some hardcore DnD rules for games, where all aoe skill also damaged your party. Though I must say, you already need to watch where to use that ability, so that it doesn't remove some surfaces you have placed in order to prevent enemies from getting to you etc.
Personaly I found totems, which are quite strong and can be cast every turn much more closer to something that could be called op, but I still would not want to nerf them, maybe rather fix AI pathfinding :P or buff few armors. + It's not like AI cant use those skills against you too and should, maybe even more.
