Melora has yet to decide where, exactly, she stands in this fight. Unlike Avandra and her allies, she does not agree that Tharizdun and the Abyssals are the great and terrible threat they are assumed to be. Melora resents the total disregard the kindgom of Easteral had for her, and was angered terribly by the spell removing the chromatic dragons from Arkhosia. In her view, this was a terrible disruption of the natural order (in a way, she’s right), and the mortals are now justly paying the price for their crime. She believes that, were Bahamut to return, he would see things her way.
As such, the elves of Graywood and Rustwood have been reluctant to join the fight, choosing instead to send a handful of scouting parties to survey the damage and concentrating their power on protecting their own borders. Even with the disruption of the veils, those loyal to her cannot fully commit themselves against the Abyssals.
Were Bahamut to return, Melora would quickly bring her forces into Avandra’s alliance the moment he joined her.