I like this idea, a lot.
I'd like to see GV spawns implemented into this idea that spawn you a half kilometer or so back from your side of the front line. The spawns would dynamically adjust as the frontline does. It would have a few "key spawn areas" of course, so people aren't spawning randomly along a 300 mile front.
Would really add a tension to the GV element, IMO. The enemy spawn gets closer and closer to your fields and strats as you defend, and the only way to move it back would be to capture nearby bases, or take out strategic targets.
Would also eliminate spawn camping to some extent. You could have a spawn camped, and then as the front line moves, the spawn does too.