Vehicles
I like the idea of upgrades/customization of vehicles. IMO it makes more sense than improving them/pilots via XP. For example after using vehicles in missions for a certain amount of time/turns/kills a new research project becomes available... something like "After analyzing numerous mission reports we believe we identified several opportunities to improve the utilisation of infantry fighting vehicles in typical combat scenarios involving alien ground forces.".
This then leads to a few minor research projects for adjusting hardpoints on the vehicles like armor (heavy armor=more HP but less AP, light armor=more AP but less HP, resistant to one damage type but susceptible to another), armament (damage vs. accuracy vs. AP cost) and powertrain (total ap, ap cost for turning/driving over stuff). Nothing major or too complex, just some choices to accommodate to personal playing styles. And I think the adjustments shouldn't be very high (maybe +/- 5%) so a fully specialized old tech vehicle can never outdo an unmodified next generation vehicle.
Of course something similar could be done with the jets as well.
Tiles
Instead of a complete new set I'd prefer more variety/assets in those sets we are going to see most of the time.
Female Soldiers
Not plausible, doesn't fit the setting, lots of work for little benefit. IMO a waste of resources. (BTW what will you do if some >$125 pledger on KS happens to be female?)
More Misson Types
# Destroy Alien/renegade Facility by escorting a refitted, remote controlled Hunter carrying a bomb (maybe including non-combat specialist/technician) to a certain place and leave before the bomb's timer runs out.
# Same as above but inverted: Aliens/renegades planted bomb and squad has to defuse it in time.
