What about a game where each player is doled out a theme/element, and set up ground rules to make it so that only certain combinations win.
Say, you can have multiple gods of
be a victory condition. Alternately, another winning condition could be to compose a team of one of every elemental or sorcery magic. Or "good" and "evil" -- relatively speaking, AWNS vs FEDB, FE as evil given that both have a fallen elemental royalty, BE self explanatory 
.
I'd imagine identities would need to be disclosed at the start of game as there's already plenty of options for treachery in the combinations of teams involved. Second guessing a pretender's theme is going to be a pain in the butt. Given that rainbow pretenders are often a lot more fun IMHO, perhaps substitute magic with some other categorization, whether historical, geographical, or thematic.
Such a game would give some pretty interesting diplo options while keeping neat team game dynamics.