No point in a new version of Falcon 4. All they need to do is sign an agreement with the BMS crew, use what they've created and then have the Microprose engineers create a new terrain/graphics engine to integrate all that with. Something where the terrain is one layer, and then there's a second mesh layer to simulate the Falcon 4 engine's terrain system so everything BMS is build around including the campaign engine can snap in with the new terrain.
I don't write code anymore, but that's what I would think of doing. A modern multi-core system could be used, so you have one core doing traditional BMS stuff, another doing new terrain, and a third doing the layer. Think of it as a kind of wrapper, but for an engine within an engine.