Ammo's numbers are irrelevant. Ammo is an exception to the mass in the MA. Ammo's choice of planes, and his performance are not typical of the norm. Ergo, his performance and record should not be used to determine the perk system.
Urchin singled out BlueMako and checked his stats and aircraft standings. Mako belongs to a squad that uses primarily the P51D. Given that fact it should be understood that he would be upset that anyone suggest it be perked. That would mean he was spending perkies everytime he flew.
I have gone through extensive studies of this perk system. I know what planes give the best perks, and I can tell you that removing the P51, FW190D-9, Bf 109 g10, and La7 will leave one ride that will milk perks. The P47. There are planes that give better perks, but you won't get more perks per sortie than the P47 will. No two ways about it.
Yes, the P47 returns more perks than any of the above aircraft, even now. Let's test that out.
P47-D25 kills Me262 : 31/5 = 6.2 perks
P47-D30 kills Me262 : 29/5 = 5.8 perks
109 G10 kills Me262 : 22/5 = 4.4 perks
P47-D11 kills Me262 : 18/5 = 3.6 perks
P51D kills Me262 : 18/5 = 3.6 perks
FW190-D9 kills Me262 : 18/5 = 3.6 perks
La7 kills Me262 : 15/5 = 3 perks
This is indicative of a single kill only. The ammo load on the P47 allows for it to carry home several kills every sortie. Now, true, you won't be killing several Me262's, but let's test out the perk system another way. Let's say ammo flies the D30 and hunts only P51D's, and he lands 1.75 kills every sortie (his current average). So, (31/18)*1.75 = 3.01 perks every sortie. Now, since I was one of the P51's that killed him I know he doesn't always fly the Jug, but you can see where this would benefit him. That A6M will be your undoing, ammo
By sticking to the P47 and taking home more kills per sortie you'll get the perks you seek, and be ahead of everyone that has to 'buy' their ride.
Should the airplanes named be removed, another would only come to the forefront.
HT and Pyro have this figured out very well. They have to have a plane base from which to determine a reward system. It is given that some planes initially released as perk rides may not, in truth, be worthy of that status. The ENY's are calculated carefully, and I don't believe they have all remained the same, but I think they haven't changed much. That implies considerable thought has gone into the perk system as it stands.
Don't mess with it!
I don't for a minute think ammo is being selfish in his suggestion. Ammo is talented and may consider it more balancing for players like him if the system were modified in the suggested way. On the whole, however, players are not so skilled.
Finally, we keep hearing references to WWII and the time frame of aircraft introduction. Of what relevance does this have for this game? I submit that it is irrelevant. If, you would only think of the aircraft available as tools in a drawer and select the tool best suited for the current situation at hand (during game play), then you would see more logic in the extent of selection.