More suggestions on top of the previous ones:
Add a city block level, where:
- Gerwalk = capable of high hover-speeds on ground and short bursts for jumping over obstacles (bridges, low buildings etc.);
- Battroid = low speeds, shooting around the corners, footsoldier;
- Fighter = Fly up the city over buildings at high speeds.
Make variants like in the jungle (seen in Macross Zero), in canyons, old Indian ruins in S. America, alien worlds (not per sé aliens, but the enviroments)... etc.
If that is possible though!