The issue is ENY should be a judgement of the plane's capability overall. Take away the ord from a P-51D and is it really 5 ENY? It's fast, has decent guns, and doesn't turn that great.
Is the D9 really that good to have 5 ENY? It's fast, can carry 1 bomb, and really can't turn well but can stick stir like crazy.
I think it would be interesting to take those few planes and perk them at say, a base of 2 or 3, for a month, and see what happens. But, as stated, people would get upset and we already have a fragile enough player base.