Withdrawal from all NElf territories from Azshara right down to Silithus and Gilneas. The Alliance should be smart enough to realise that a: Sylvanas wasn't really touched by this war and b: she isn't really controlled or constrained by the Horde so there isn't any point addressing the concerns over her.
The Alliance to finish the road linking Theramore with Stonetalon and the right to maintain the forts and troops there
The Alliance to provide material aid to rebuild and restore Durotar in exchange for guarantees of non aggression.
The Alliance will provide formal recognition of Horde territory - Northern Barrens, Durotar, Mulgore, Echo Isles, Eversong, etc - and will respect those borders once defined. They will make no such promise wrt Lordaeron outside BElf lands.
There'll be other issues - Kor'kron to be disbanded for example.
Not sure what they can with the Forsaken or Sylvanas....with the Horde essentially defeated, the promise of protection they provide is very much devalued. This SHOULD be the time frame when she openly begins to prepare to leave the Horde, build up her independence and reserves but there are some rather obvious issues with that.
Neither do I. The Hordes protection, the aspect which Sylvanas wanted, is effectively gone. They have no hold on her, nor do they offer her anything of much value.
I can see the Alliance getting the Horde to withdraw from the NElf territories, perhaps with some consideration for Bilgewater harbor in Azshara (actually - I'd like them to replace it with Gallywixs supper-zepp; give the Horde a flying fortress).
Ideally - this'd be shown in game in some manner, even if only with some more Alliance NPCs. The Alliance players,. I still think, need SOME immediate impact and payback.
But Lordaeron? Sylvanas will leave the Horde if it tells her to do that. The best I think the Alliance can perhaps get is to try and limit the support that she may get from the rest of the Horde....but they'd likely just do it anyway simply to tick the Alliance off.
EJL