Fighter Pilots should get double XP for killing an attacker plane, and triple XP for killing it before it kills anyone in your team.
The reward for Best Engineer should be given to the person whose fortification is used the most, not just the person who gets the most XP while just so happening to be an Engineer.
If you equip Repair Tools to a non-Tanker soldier, you should get +30 XP for repairing a friendly tank.