There won't be any free planes added given the amount of work required (even if AI is already there), and I sure hope they won't waste time with playable ships or tanks as this is an area that they have no experience in, will require a lot of work and result in questionable gameplay value. I don't see the point of making another "Battleground Europe" at all (in fact I can't see the point of the original one either
).
If some 3rd party is interested in adding stuff, fine. And AAA guns sure could be fun, but this is pretty much where it ends for me. There are already enough interesting and important additions to the flight sim part that will never happen, even without diverting resources to different areas.