I'd go with the concept of semi-permanent terraform. As in after each battle just cast a 50% restore on all the areas of the map (as in restore all but half-done). This would make the ground more playable, while retaining most notable deformations.
With deployment I'd love to see every player on the defending team to get a bunch of flying boxes that can morph into some static defenses early on (e.g. an DDM-like turret with radar, and a long-range TL with AA for sea), while the attackers get some extra metal for the early raids and map control. The flying box thing should have a limited deployment range (so that it can not be placed in the enemy base). This would enforce somewhat asymmetric gameplay, focused around static defenses for defending team and around assaults for attacking team.
Also a funny trick can be done as in the more dropships you send the more starting metal you get.