My idea:
+ Reduce the maximum multiple possible of the determination, from 6x to 2x.
+ If a region is liberated, that territory acquire a protection status for 7 days. Hence, the previous occupant country can't declarate NE, War or Airstrike against the original owner of that territory. Of course, any other country can attack it via NE, War or Airstrike. If between that status' time, other region is liberated, the protection status is extended for other 7 days.
Greetings.