In my mind i've always thought that she was as i said a compromise because she isn't dangerous to any of the really old ones, so essentially they reestablish the old ways ( Elven Court, path of the Wheel..etc. ) but without loosing much of their own power because of a strong queen like back when Alachia held the Throne before the scourge.
You see this bit I really don't agree with. Tir na Nog isn't a copy of the Elven Court created with the cooperation of Alachia, it's a revival created by a young immortal who's arrogant enough to think she won't make the same mistakes the previous Queens did. Brane Deigh isn't there because she some compromise candidate, she's there because this is she wants and no one is going to stop her.
I'd extend this to all the neo-elven nations, they may cooperate to some degree but they're not part of some single elven master plan. Different individuals and groups are working independently. The heavenherds in Azania creating some analogue of Thera, the Danaan Mor in Tir na Nog recreating the pre-scourge Elven Court, the YETs and Ehran creating something new with elements of the ancient in Tir Tairngire.
As for Alachia she's like Harlequin. She's too powerful and has experienced too much to bother with nation building, at least while the magic levels are still this low.