Personally, I think the Kills over Time is the big one that sucks. It definitely rewards the vulcher, and really has nothing to do with actual skill in most instances.
Another good one would be an additional bonus for ENY difference. If you're constantly owning people in 5ENY planes with 35-40ENY planes, it should count as higher.
I felt really bad with a 26 Kill streak in a single KI61 sortie -- 6 of which were from well placed bombs on two formations of bombers. It also is a bit crappy that if you shoot into the cockpit of a buff on the runway, the next one automatically jumps into that position, so one short burst can instakill all 3 buffs with very little use of ammo, or having to change your point of aiming.