Fangorn isn't exactly the best faction for ANYONE. Its only worth getting +1 or 0 alignment just to avoid the wrath of the trees or for ent-draughts. You can hire Huorns, which are some of the best troops there, although it requires 500 alignment. Getting that kind of alignment is rather difficult especially considering that Fangorn has NO mini-quests, which are my (and most likely many other players) main way of getting alignment.
So, I suggest this - the Golden Ent-Draught (huorn hiring one) should have an alignment minimum of 300 or 350 or 400. Considering Olog-Hai and Mirk-Trolls are about 400 to 500, that should be a good trade off. Other Ent-Draughts should have an alignment mimimum of +1, and with enhanced effects (longer for 30 seconds) for every 100 Fangorn alignment one has.
[EDIT]
Dark Huorns should spawn uncommonly in Fangorn, and effectively serve as a way to get Fangorn alignment (kill them) as well as a way to get wood (each Dark Huorn drops their wood, ala Old Forest). However, Dark Huorns should not spawn too close to Ents or normal Huorns, as then the Ents would just kill them.
Edit: Removed redundant noise from title. ~Alte