Not agree, with anyone of you, Firstly isnt important that erebor is the unique subfaction that have it, I mean, what about balin runes, or highspeed dwarves from ironhills? Camon, this isnt a great advantage, only give them more chances to siege. And the strong of this siege machines is that if you use 3 you can get a extreamly high damage to multiple buildings, or a lot of knockbak in enemie frontline, allowing you to destroy your enemie with axethrowers, so hell yeah, this siege machine is very usefull, and Ered Luin is enough Op for now, ironhills maybe could get Ballistas like a summon of Drar instead of his sabotage abilitie. And this units is very underestimated by many players, is very usefull not useless, but yes, its damage alone isnt enough, maybe can get buffed ;D