Actually, it seems to me that ENY doesn't noticably encourage EITHER side switching or an arena change - what it mostly seems to do is encourage sitting in the tower periodically checking back to see if it's dropped while you are waiting for "your" ride, or bellyaching about it over country radio ...
BaldEagl would like to fly with his mates, and either can't get into the arena where they are already playing, or if he does get in there, can't choose a ride he wants to fly. In and of itself, not unreasonable things he wants.
If was to suggest a change at this point, It would be to add a perk bonus/cost to changing sides based upon the numbers. Perhaps something on the order of a bonus of 2 x ENY as an incentive, and perhaps a smaller bite (1/2 x ENY) to change to the higher numbered side. (Otherwise, people might refuse to change to another country knowing that they'll eventually be switching back to fly with friends, and not wanting to risk a loss of perks to switch back.)
If this worked, it would encourage more people to change sides and balance things out. And if the people playing in an arena balance the arenas themselves, it eliminates a lot of issues.