Not sure what a "floating front line" is...or how you're thinking it would work. If you're talking about bases moving or popping up as sides capture territory, that would require a complete re-write of the game and complete re-write of the terrain editor and maps.
If you're just talking about concentrating the fights to just a few "front line" bases, I think we already have that capability. The problem is that not everyone wants to be in a 30v30 fight between two bases 25 miles apart.