Maybe I can make sense of this.
Dragon= Imperials, Skyrim, Hammerfell and High Rock under a tentative empire(We REALLY need an exact date for this thing to accurately guess).
Phoenix/Eagle= Aldmeri Dominion: Valenwood and Summerset.
Lion= Elsweyr with a loose and uneasy alliance with Argonia. They do not exactly love each other either.
Neutral Party- Morrowind. They are the only nation at that time to have no part of the Empire other than a war that they won. They have the Tribunal at the height of their power. They are arguably just as powerful as any other group. Yet they would not identify with any of the other powers. They do not like the Empire and they have shown they will viciously defend themselves from them, they do not have a good history with the Human races. They HATE and distrust the Altmer and have a completely different metaphysical outlook. They don't even consider the Argonians or Khajiit as people. Just potential and easily gotten slaves. Thus I say they will be a Neutral party.
I like the direction taken here. I think what got the most excited about TSO is the fact that we have the Tribunal again (Something that made me personally incredibly happy after hearing what happens to the Dunmer in the 4th). I am very interested in seeing the Tribunes at the peak of their power. Hell, we might even see some of that benevolence we heard had long since passed. (I personally want to meet Almalexia being kind and loving, just to think "in about an era, I'll be killing you"). But I digress....
My only difference in opinion with you Albinodumner is what I think the Lion represents. I agree that the Dragon is the Empire and the Eagle is the Elven Nations (a manifestation of the Aldmeri Dominion?). However, I believe the Lion may very well represent the Human races, most specifically Skyrim. While my math may not be the best, a millennium (1000) years puts us in the Second Era, somewhere in 2E400s. According to TIL, the Aldmeri Dominion was well at work (http://www.imperial-library.info/content/rise-and-fall-aldmeri-dominion) and the Potentate is now dead. The First Empire is in shambles (http://www.imperial-library.info/content/second-era). Look specifically at 2E430 (That's roughly 1000 years from the events of Skyrim). However, the Lion still remains as the question.
Throughout Skyrim, I was personally annoyed by the lack of a third option. It was either pro-Thalmor controlled Empire or pro-anti-Empire Stormcloaks. Has it not struck anyone else that there is a third path that should be available, quite simply one of imperial rule without the dominance of the pesky Thalmor? This theme could very well have gone into TSO, in my opinion. The Lion represents the Humanoid races, specifically the approaching Humanoid savior and herald of the Third Era, Tiber Septim (the Dragon). However, the twist here could simply be that the Lion and Dragon become one by the end of the Second Era. Talos is representative of the Lion (Nordic/Breton) but claims rule over the empire (Dragon). As a result, the Lion faction or icon is not as relevant in future events because the two were made one. The Lion BECAME part of the Lion (Hence the result for all the lack of understanding on what the hell the Lion means).
The resulting faction breakdown is therefore one of a spectrum. The Eagle is the Elven Extreme. The Lion is the Human Extreme. The Dragon ultimately is the moderation between the two by swallowing one (the Lion) and becoming the new extreme. This extreme will ultimately triumph thanks a particular stompy robot. However, the role of outside parties, such as Morrowind, Elsweyr, Argonia, and Orsinium can not be underestimated. I predict the changing of future events will ultimately require the gaining of the support of these different nations/factions before the opposing factions do.
And hell, to me, that sounds like one incredible game. The Second Era is one of discord, chaos, and revolution. I would love to see us fans playing out that revolution first hand. As for Molag Bal, well maybe we have two different crises to deal with at once. But then again, it would not be the first time we have two major conflicts to deal with at one time.
My $.02
Walk with Virtue Outlander.
-Hexon