For me you are doing exactly the right thing by releasing the 1st component as soon as you can (so long as its debugged - though if you need a beta tester I would volunteer).
Personally I rarely have time for campaigns and suspect the only a small percentage of users actually do fly campaigns. attack
Historical missions very important, but the capability for 'what if' missions also very important.
Given that
a, Jerry Pook strongly supported the idea of RAF Harriers flying A2A (no surprise...)
b, The radar on the Sea Harriers was quite variable in performance
c, Many of the Sea Harrier interceptions were eyeballed from CAP or from GCI
there is lots of opportunity to provide A2A.

You haven't mentioned the mission editor ... I think it will be very important to have that capability in the first release to leverage the community enthusiasm to produce content.
Hopefully your mission files are ascii ... I've written a number of complex to simple mission editors in the past (see here ) copter
Cheers
Keith