[*]Flight/Kette integrity and consistency: keep the flight members the same unless wounded/on leave/missing, and keep the ranks historically accurate. Add in promotions and being transferred to other flights/squadrons, new guys coming in with v. low skill levels, etc. Just generally more realistic flights/Ketten, which were after all the primary combat units in reality IIRC.
[*]More French 2-seaters (i.e. Breguet).
[*]More encounters with lone or pairs of 2-seaters doing arty spotting or recce. 2-seaters usually seem to appear in flights.