Hi,
as already said, mechanical failures would be great (random and damaged induced), but the mission success/failure must be adapted: sometimes it's already a big success to come back alive (especially during bob)
a few suggestions:
Some historical anecdotic facts during briefings/debriefs are usually an easy way to improbe immersion IMHO/
bird strike and freezing conditions in altitude causing trouble is a great idea !
bail out: make it possible to decide when to open the chute
Is oxygen cunsumption modeled at high altitude ? Kaboom, a hit in the oxygen tank and you'd better dive an max Vz not to collapse
-search and rescue mission objective bonus would be great: a wingman is shot above sea, and you orbit a while to help recovery by SAR
- if IFF and radar is modeled: identification errors , with ground control asking you to check, friend fire accidents with fighters or flak....
just a few ideas, the project seems already great !!