When it comes to squad shooters, I always think about how fun Fallout Tactics was. Imagine, once Fallout 3 comes out, some kind of mod that is basically Fallout 3: Tactics?
Same game concept, squad of up to 8 completely customizeable chars who basically go and kick lots of post-apocalyptic ass and maybe they'd be able to switch it to give it a Freedom Fighters take, as in you're always in control of the main character, but he commands the others around but you can switch between them.
It might just be me, but Fallout Tactics in 3D instead of Birds Eye (no offense to it) with a cover system, and the benefit of actually shooting things as opposed to just clicking, sounds freakin tits.