Seat switching is a skill that requires practice, timing, and altitude. Not everyone can do it. Those who can't do it call it unfair and cheating. KGC and Griffin are great servers and have everything setup nicely except the disabled seat switching IMO. Thankfully, Easy Prey Death server allows seat switching in spite of periodic grumbling from seat switching opponents.
Even in the real world, most military attack aircraft allow the (flying) pilot to fire weapons if the weapon station operator (co-pilot) is absent or injured. For example, in the Mi-24, Mi-28, Mi-35, AH-1 Cobra, AH-6 Apache etc., the (flying) pilot is equipped with an emergency set of buttons/controls and an optional folding HUD to fire weapons if the weapon station operator (co-pilot) is injured, incapacitated, or absent. Similar provisions are available on other Russian, American and European attack aircraft too.
Seat switching is an attempt to use real world features that EA forgot to incorporate in the game.