There's no reason the criteria behind perking things cannot be changed, Ack. "Balance" is only one of the many reasons possible(and the only one currently being used) for considering things to be perked.
Also, to apply a reverse logic, your reason for them being not a problem, doesn't sound much different from "I have no trouble killing them, so they have no problems".
If most of the average pilots who are probably significantly more in numbers than the guys who always have no trouble in killing things, thought the same, the "Big Four" wouldn't be a 'big four' in the first place.
In short, the Big Four is a Big Four because most of the people don't agree with you. They're either 1) harder to kill than other planes, 2) easier to survive in than other planes, 3) easier to get kills in than other planes, or 4) all of the above. That's why they fly them. Lookit the hoarde of average/newbie pilots using the La-7 - despite that fact the plane still has a K/D of over 1.
Thus, four planes constitute 40% of the arena - jabo/CV ops not included, only at a pure fighter role. That's about as high a percentage the Chog got in pure fighter role(10%).
If that's not 'unbalancing', what is?
The super high perk costs suggested above for the N1K2, for example, clearly comes from a personal bias. But that doesn't necessarily mean the whole idea of perking things is a no-no.
