[Mightypeon]

I think Fomoria is very well balanced.
They arent Niefelheim, or Lanka, but between recruit anywhere minithugs, recruitable SCs, excellent Air and Death access they do have a number of things going for them.
Even the much maligned Fomorian militias can be suprisingly usefull in a Siege defense due to low cost and S.

And dont underestimate the Fir Bolg troops either, the Javelin guys are actually quite good.

To summarize it:
Formoria has a quite decent early game with Unmarked expansion backed up by quite good Fir Bolgs, can rely on early recruitable SCs in the Midgame (Construction 4 and alteration 2), and is well disposed for Tartarians/High End Air Summons in the late game.
Dance of the Morrigans (especially if backed up by other spells) is also strong.