ENY is a non-issue as far as I am concerned. I happen to fly a bird that is not affected either way. As for perks I rarely use them.
Really ENY just affects those that refuse to even up sides and those who fly perked birds.
Just because you choose to fly birds that are rarely effected by ENY does not mean it is a non-issue. Especially because under the current system several VERY competitive birds have inordinately high ENY values.
You can argue that in a perfect world people would switch to keep the numbers even, but this does not happen. There are some understandable reasons for this besides chess piece loyalty (inertia, people's squads+friends typically fly that side so they want to stay, etc.), and in any case, in arenas with hundreds of people such side evening would be very difficult to coordinate. So ENY's functions there is needed, with all its imperfections.
I hardly ever take up a perk bird myself, but there are lots of people who do. Lets face it, the majority of players can't earn perk points hand-over-fist practically at will with most any plane, unlike most people posting on this forum. So relating a plane's ENY value to what it can actually do would be vital to fairness even if numbers were always even.