Hhrrrmmm, while this is a very cool scenario I feel it's jumping the gun a little. Going to eighth level spells is a huge leap from where we were before. Not only does it imply a lot of research it forces us to create roles for high level characters in the societies in question. Decide how they get they created and used by the societies in question.
Also any massive invasion from the outer planes brings up a lot of questions about deities that we haven't answered.
I also question how much business Ta'jinn and Cressia would be willing to do with Ausel. The Auselens screwed them over in the last war and all of the factions knew about and it and none were happy about it. The current understandings between the Khanate and Cressian sort of hinge on their hatred of Ausel. And I don't see the Khanate and Greater Cressia engaging in much brinkmanship and arms racing as the Khante views Greater Cressia as securing their border and running their border so that it might turn its attention elsewhere.
I do think that additional powers need to be introduced into the scenario and I had hoped that the understanding that resulted in Greater Cressia would result in the Auselen expanding out in the direction of other lands and thus expanding the scope of the world and its conflicts.
Those are all questions of set up for the scenario, however, and I think that there are still a lot of kewl issues to be addressed and dealt with here. Just some adjustments to be made.
That being said, I would say that there while there are probably a fairly large number of high level of adventurers and characters scattered throughout Greater Cressia the highest concentrations are in the following centers, in no particular order:
-The Memorial City/the City of the Games: The high command of the Confederacy established an academy around a hundred years ago to create projects that would use the talents of the most experienced and learned individuals in Greater Cressia. This community is largely self-sustaining but a mysterious group alternately known as the Deans, Wardens, and Minders (depending on your cultural origins) possesses both the highest official authority in the community and a powerful template given to them by the combined powers of the Cressian Deities, Stempan Oracles, and Ta'jinn Blood Spirits.
-The Oracular Enclosures, Cressian Hierarchy, and Ta'jinn Councils
-The city states, guilds, Ta'jinn orders, and Tamarchs
-The Empty Quarter, including the Ta'jinn Foriegn Tamarch, Cressian Ceremonial cities, dark Stempa, and various other high conflict low order areas.
-Various small or fluid communities of adventurers, such as the Inn of the Coral Breaks in the Cressian port cluster of Rarshun in which a high powered market of unusual items, a community of sages of arcane lore, foriegn embassies, and some strong guild posts and temples are located. From this city many adventurers derive supplies and information for their risky undertakings and customers for their goods. Many adventurers come to settle or retire here and many institutions recruit heavily here as well as vie for the many innovations in techniques, technology, and learning that the unusual populace produces.