I'm pretty certain ENY is to encourage people to switch to the low side to assist in rebalancing. removing eny would make the side balancing worse. I do not think it is to make it more of a "fair fight" by giving a disadvantage to the side with higher numbers. If I am wrong and it is the latter, then I would seriously question its effectiveness.
If I am right though the carrot dangled to switch sides works for some, and not so much for others because some people would rather be loyal to their team or fly with people they know while for others and me personally, I see it as "oh boy! I can afford a 262 sooner by switching"!
Either way though I think everyone can agree that the majority of the time balanced sides are more fun, and unbalanced sides are less fun. In times of fewer players the imbalance can overwhelm the metrics in place to prevent it.
The issue imho is that ENY does work as a perk (see what I did there) for some, but also as a punishment for others. It totally sucks to log in wanting to fly what you want, and not being able to because there are too many players already on your side. Something you have no control of, unless you switch yourself, which you may not want to do.
My solution is to make switching sides a purely reward based system, rather than a reward/punishment (as some clearly see it). Lock the ENY to base 1.0 and when the balance of sides deviates past a certain percentage say...15ish% double or so the perks for anyone willing to switch for the amount of time they must stay per side switching rules. Make it obvious too, like a pulsing green highlight on the "officers club" tab and then on the "change country tab". When the balance normalizes the highlight disappears and players become ineligible to receive a bonus from switching.
Heck while we're on the subject of rewards and highlighting, wouldn't it be super fun if there was a perk bonus on a specific aircraft each hour? For example: Each country has a different and random aircraft that would be highlighted in the hangar to receive bonus perks adjusted for its ENY when selected.
Or perk bonus for joining missions...
Or perk bonus for some achievements...
Actually if the ENY was always base 1.0 perk bonuses could be rewarded for all manner of things to make the game more enjoyable, but that's a different thread.