My dream game would probably be PlanetSide 2 but without the horrifying chain of bad decisions, executive meddling, and dev team losses. I still love the game, but there's a lot of things that have gone wrong. If anything, it's great that despite all the bad things that happened it's still a fun game with enough people playing it five years later.
So I guess the dream game is basically merging PS2's shooter gameplay, maps, and faster-paced action with some of the more intricate strategy that was possible in PS1.
Also, I'd make Vanu's small arms niche more unique. Honestly, making each faction have their own damage models would be a good start. I'd play up aymmetrical balance more and actually let everyone steal things from the other factions (hey, that was in PS1 too!) so even if you think the Prowler is better than the Magrider you can just hack one out.