The %sorties argument does not work. Here is why:
Some apparently want a plane to constitute 20% of all sorties before it can be perked. However, the only plane that ever achieved that was the C-Hog back when the game was young and the plane set was much less varied. I believe that if you today unperked the C-Hog it would not capture 20%. In fact, it is mathematically demonstrable that it is very unlikely for all the currently perked planes to capture 1/5 of the MA "market share" ever again. Tempest, F4U-4, C-Hog, 262, SpitXIV (leaving off the 163 because it is not available arena-wide.)...five planes, each with a lot going for them. If the whole MA flew ONLY them, in equal numbers, then they would have 20% of use apiece. If they were NOT flown in equal numbers, then one of them would fall below the 20% benchmark and thus would deserve to be unperked...right? And of course, not everyone in the MA would actually choose one of these five all the time, so the chances of all five currently perked fighters consistently achieving the magic 20% of all sorties would be nil. I would be surprised if even the Tempest alone managed a consistent 20%. It would be interesting to check use stats for the DA lake if possible. Just off the top of my head, I don't think the crowd is typically anymore than 50% perk rides, probably less.
So since use stats are useless, what are we left with? The cold hard performance numbers of the plane relative the rest of the set, numbers which a great many people opining on this thread appear to have been ignorant of. Most especially, if an airplane's numbers show it to be double-superior to very large chunks of the plane set under typical MA conditions, that to me seems like a far better argument for perking. Far better indeed than notion that if, say the P-40B, achieved a certain use benchmark it would need to be perked.
I do not think perking the SpitXVI would "force" people into fly any plane, especially the Pony, an airplane inferior to the SpitXVI in every respect except top speed and requiring a totally different style and mindset.
Rather, I think it would *allow* people to fly a wider variety of middling-performance aircraft without eventually getting frustrated and saying "Screw this, I'm taking up a Spit!", or just grabbing one the really fast b'n'z planes and avoiding committed engagements with SpitXVIs around.