I wouldn't call the D&D attack wing a concept proven. Sure you can flight-path system for any game but that would be like playing Imperial Assault with GURPS rules. Sure the flight-path system fits perfectly with X-wing but doesn't naturally fit anywhere else. Also how would initiative of troops and vehicles work? Aircraft can react faster than vehicles while vehicles can react faster than ground troop formations.
FFG knows this which is why they didn't just do a D&D attack wing when they made Imperial Assault. It would be nice if we had a ground combat game that was compatible with X-wing but in order to be a good game and not just Star Wars Ground wing there will have to be at least new movement systems. And that will add complexity into the game that many players would consider unnecessary.
Just take a look at Epic, the mere addition of a unit that was not a star fighter had to come with it's own separate set of rules and maneuvers. That right there makes Epic games take longer than Armada which is a big turn off for many X-wing players. Now imagine that with two different unit subsets one for infantry and one for vehicles. It will be very difficult to streamline the game system to include all of theses aspects in a reasonable manner.
