We are assuming a lot of things here....Lets assume that the Bosmer rebelled(The Khajiit are still with the Dominion)..
The Nords,Redguards,Bretons and Imperials formed an Alliance to unify tamriel under one banner and one leader(possibly the next Emperor)
With a successful bosmer rebellion the Dominion has a foot hold in Elswyer and Alinor but their presence is limited in other provinces such as morrowind.
The Dunmer and Argonians decide to remain neutral in the confrontation.

Main points of discussion
1.The Battle Strategy
2.The role of the various factions in the war(i.e Fighters Guild,Companions,Synod,College of Winterhold,Thieves Guild,Dark Brotherhood,The Blades and The Dragon{not really a faction but still})