There is already a perk cost modifier in the game based on country roster. That was tried first, before ENY. It wasn't effective.
My question to that would be why do players generally look at the roster? 90% of the time I'm doing it I'm either looking for squaddies, specific players or viewing stats. The effectiveness of a display like that is strongly tied to where you place it, much like advertisements. A better place (and this is just plucking ideas out of the air cause I'd rather pretend I'm still on lunch) would probably be on the hanger screen showing how much a plane costs to you now, versus the cheapest available. I can't say whether or not the difference would be large enough to make it useful though.
limiting them to lesser rides, or giving them free perk planes to fly with the outnumbered side isn't going to change anything.
It does change something, it changes the cost of the planes. Whether or not that is going to have a more significant impact on providing incentives for players to switch sides than exists now is up to interpretation.
The details of the idea really aren't relevant, I think the whole reason I posted it in the first place is from a design standpoint it is far more valuable to a decision maker to be provided options. Having a group that says 'NO' and having a group that says 'YES' but provides absolutely no additional value in the way of ideas for potential improvements is fairly pointless. And that comment is directed more at those who want ENY to disappear.
If you want to be rid of ENY there's going to have to be something better to take its place because it doesn't seem like HTC is inclined to return to pre-ENY days due to the lack of a balancing mechanism (regardless of how effective/ineffective it is).