Things that are gonna be added from what I've seen:

1. Airfoil
2. Better fuselaging
3. Camouflage
4. Better afterburner
5. Major Chad
6. Multiplayer
7. Heathaze
8. Volumetric clouds
9. Better graphics
10. Underwater
11. Underwater engines (probably)
12. Better physics (probably)
13. Weather (probably)
14. Better destruction
15. New and bigger map
16. New weapons
17. Better landing gear (probably)
18. Better interiors (probably)