This is just an idea I had - not sure it's a good one, but I figure I'd share it and get some feedback on it at least, perhaps even hone it into a half decent idea
The initial premise of it would be that there would be 3 teams and 3 bases. Initially, the bases would be uncontrolled, and all players would spawn away from the bases, leading to a rush to capture a base.
Once you have a base, the focus would switch to capturing the other bases, whilst defending the ones you have. A win would be acheived by capturing all 3 at the same time, with a major points boost for doing so.
In terms of capturing the bases, my first thought was to have flags spawn in the middle of the map, one specifically for each base, and shared between the teams. These flags would return instantly when dropped. Either that, or a Warpath-style "no flag required", but I think that would likely make it too easy to capture the base.
I think the main problem with it would be balancing the defensive capabilities of the bases properly. They'd likely need to be set up to be quite easily defendable, as much of the team would be out capturing the other bases. It'd be aukward to get right, thats for sure...
Anyways, any thoughts anyone has are welcome