Currently, AH players spend about 28% of the time 'in sortie' per tour in GV vs 72% in planes. 
I don't doubt your stats but frankly I am surprised it isn't higher. When you have a map that contains 18 Af and more than that for Gv bases/side then it seems logical many conflicts will be primarily ground based with limited air support. More drivers than fliers.
Sometimes circumstances dictate the best choices are GVs particularly if a base is captured that spawns into an enemy strat fac. I could take the time to climb and go there in a bomber to maybe drop strat 30% with good hits, risking attack inbound and outbound; or I could up a Jeep and drop vehicle supps then return in an M4/rockets and take the strat down to 0% in less time than it would take to reach target in a buff. Not a really hard choice if my goal is to damage strats.
As to the topic of game balancing, I don't believe there is a way that will always work and always make things fair. ENY is an attempt at that, but even a great plane isn't a match for a swarm of older models. I've just come to accept that this is a game about butt-kicking; sometimes you gives, sometimes you gets. If someone doesn't accept that - and I imagine every country has those who scream in the text buffer until you want to take an Excedrine - its only going to lead to them souring on the game. But that's their loss. Why pay to have fun if you spend all your time making it NOT fun?
I like to use those times my side is getting stompped to fly planes I normally wouldn't or go drive a vehicle I don't normally drive. going to get killed anyway so why not learn something new?