[Clans instead of Alliances]

That's not a bad idea. Also you will have to make sure there are ways for members to truly interact with each other. To many games use clans and alliance as just a way for members to chat if they so choose. Though not actually benefit from being with these select players. Like group cooperation or defense and why not.

[Geography of players]

Illinois, US here I know some people who were big on ingress that would likely join this. I will need to convince them.