(Sticking with the 100/100/50)
So, in your version, the closer you take off to the outnumbered side, the higher the ENY, forcing you to choose poorer aircraft to launch in. Additionally, the closer you die to the outnumbered sides field relative to the distance from your own, the higher the cost of dying in terms of perks lost, by some ratio of your side to their side in combination with the "original cost" of your plane.
1) Some people have mammoth numbers of perks. How do you deter them from going back as far as they need to to launch the lowest numbered ENY aircraft, and not caring about the perks they might lose?
2) How do you deter a pilot with no perks from caring that he's going to lose some of what he doesn't have, and taking off from a field far enough away to get the plane he wants?
(edit-> Slapshot hit on these two points while I was typing away as well - and valid they are!).
3) This might be a good thing or a bad thing - I can't guess which. I think that many of the players for the sides with 100 & 100 are going to simply choose to fight in the areas of the map where they aren't affected by ENY. This sounds like what you'd want - but may not be. The danger with this design is that if enough of the the players signing into the side with the lower numbers begin simply changing sides to get to where the fights are, you end up further unbalancing things until you end up with one side being a ghost town. If there are 287 people in an arena, and only 11 of them are flying for the side you're on, how many players coming into the side with only 11 plaryers are going to just switch sides? On the other hand, the side with the lower numbers is going to have a much easier time of rolling up territory, so they can't be ignored forever (assuming that the "distance" part of the equation allows them to try to take fields without negating the effect) - that is, if enough players who care about who wins the map reset are on, which many don't.
4) What incentive is there to keep the side that has the number's from launching from behind the lines, and just defending in late war equipment near their own fields?
In the current version, there is incentive to change to the outnumbered side, a disincentive to change away from it, and no way to ignore the imbalance.
In your "design", there is no reason to change to the outnumbered side, a significant incentive to actually change away from it, and for the players on the countries that outnumber, the imbalance can be effectively ignored. On the positive, there may be additional incentive to be on the lower numbered side, if you are into taking territory, and things are carefully jiggered to make that easier.
What I don't like about the idea is that it appears to have a positive feedback loop, which I fear would eventually overwhelm any positive benefit. The fewer players there are on any one side, the less likely that anyone is going to want to fight against them, and the more likely that the players on that side are going to want to leave (change arena's, or sides, to get to more "action").
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