It would be very simplistic, yes, so it's a good thing I never said that. The Shadows want all-out war between the young races, not a single big battle. Furthermore, attacking them openly themselves would not fulfil their aims, because the young races will just band together against the common foe--which is pretty much what ends up happening this time around. The Shadows work in secret, helping out this race here, that race somewhere else, with the objective of sowing dissent. They don't want territory for themselves, whatever Morden said when talking to Mollari.