Ok, looking at your list.
P-51D = 8
F4U-A1 = 15
P47-D25 = 25
190-D9 = 15
109-K4 = 20
La-7 = 5
Of those 5 planes, which would you say is the easiest to learn to fly and get kills in, and be able to RTB?
My money would be on the La7, which puts it exactly where it should be, low.
Other end of the spectrum, you have the P47-D25 which is a much harder plane to go out and get those kills in and be able to RTB. Hence ENY of 25. Your going to earn perks 5 times faster in a P47-d25 as you will in an La7.
Why? Because its that much harder to do.
Personally I think the 109K4 is set too high, that thing is a monster.
So to rearrange your list in ENY order.
La-7 = 5
P-51D = 8
F4U-A1 = 15
190-D9 = 15
P47-D25 = 25
Would you really say that the 190D9 is as easy to fly and get kills in as the P51 or la7?
Or is the list stacked in terms of difficulty (and possibly partially popularity)
Well, i look at it as to "do you know how to fly it correctly". Example, a lot of people knows i fly the p-47D-25. I do take it at high alt and used the BnZ and know how to keep that E. I avoid turn fights because i know that it will slow me down fast and put me in a disadvantage of getting out do to the slow acceleration. The D-25 is not like the "M" where is can take on a lot of the tight turns.
La-7, i do not fly them and never flew them. all i do know about them is that they are superior below 7-8k. Why a ENY of 5 where its preformaces drops as it get higher, i do not know.
109K-4 is seriously over looked. A ENY of 20 is to high thous should be brought down to below 10. The only disadvantage with the 109 is fire power limitation put deadly if you know how to aim with it.
F4U-1A seems to be the most flown corsair. Can turn well, good gun packet age, climes exceptional, acceleration better then the P-51. The only disadvantage i see is keeping slow and low will be easy to take out.
190D-9, well personally, it is easy to fly and get kills. is it easy to fly like the spit, no. To get kills, yes far better then the p-51 and La-7 as long as you know how to fly it. That gose the same for the P-51.
So this is where the ENY should look like from my view:
109K-4 = 8-10
La-7 = 15
P-51D = 8
F4U-A1 = 15
190-D9 = 10
P47-D25 = 25
But like i have been asking, what dose it take for these AC to get that ENY value?