I've spent quite a bit of time there. The Tempest, Chog, and F4U-4 are very popular, however, just from personal observation, I don't see their aggregate use as being any higher than 50%. They would have to comprise at least 60% of all sorties flown for each to reach the magic 20% of use mark, and even at that, if one of them were more popular than the others, thus taking a bit of the "market share", it would knock the other two below the magic 20% figure. Any person who thinks about it will realize that the 20% figure is an impossible standard to meet with today's plane variety and the number of die-hards who only fly in their favorite types.
I think you're looking at it incorrectly. You're looking at the "market share" of all the unperked planes, then looking at the market share of currently perked planes when they all become unperked. Neither of those methods gives us any idea of what we'd see if
one of the currently perked fighters was unperked but the others remained perked. Were that to happen, the popularity of the C-hog in particular would probably spike due to pent-up demand, then settle to a level significantly higher than any of the remaining perked fighters. I don't know whether it would reach 20%, but I bet it would be markedly higher than 10%.
WRT the larger discussion, I don't think you're giving firepower enough consideration. It's not just that the .50s are inferior to the Hispanos, you also have to factor in the imbalance in ammo load for the XVI - you either go home early or are left with a grand total of two .50s. At that point the C-hog still has four cannons left with nearly half their ammo remaining. That is no mean difference.
There's also the issue of versatility. Some of the XVI's weaknesses - low ord loadout, low ammo for its cannons, short range, and fragility - make it unsuitable for a variety of missions. With only 240 rounds of 20mm and little ability to take punishment it's a mediocre bomber interceptor at best. It's a less than stellar jabo because of the payload, it's not a good choice for AAA suppression because it's relatively fragile, and it's limited as a bomber escort by its short legs. It's a great base defender and good, but because of its low endurance not great, as an air superiority fighter on offense. And it isn't available for carrier ops.
By contrast, the C-hog is an excellent choice for
all of those missions. IMHO that's one crucial component of unbalancing. The Spit XVI will never unbalance the game as much as an unperked C-hog or 4-hog might because there are so many situations where only a 1-plane fanatic would choose to fly it, and it's not as overwhelmingly superior at the things it does well as the Tempest, 262, and 163 are.
The last argument I don't think I've seen addressed here is who benefits. Unperk the Spit XIV, Tempest, or 262 and you're helping the experienced pilots with enough skill to take advantage of their strengths. If the critics are right and the XVI is popular because it's the best "Easy mode" fighter, perking it will hurt less skilled and experienced pilots, who have it tough enough as it is, more than anyone. It's not like the XVI is a wonder weapon that lets any 2-weeker smash through formations leaving veteran pilots and their planes littered on the ground left and right. If they're flying Spits and learning to fight and not just take one pass and run home, that's a good thing, isn't it?
I'm not big on the perk system as it's currently implemented anyway. I understand and agree with the reason for having it, but while it may be a sound strategy in a real war, in a game like AH giving better equipment to the people who already dominate the game is counterproductive, and losing the perks only when you die only reinforces that imbalance and gives people that much more motivation to fly timidly.
