Add a third control scheme just for solo play. One that is quasi-turn based similar to games like Knights of the Old Republic. Uses the standard RPG controls, but you can set pauses when your "turn" comes up or for other events that can happen in combat. Or even a pause button which pauses the game when your turn starts.
Obviously will not work in multiplayer ground missions, but will make ground combat a lot easier for players who only do Ground when it comes up in missions.