Kev.... how does the performance stack up relative to what else is flying?
I know the Spit 16 is about (read roughly) equal with the Ki-84 in a slow speed stall fight, in my experience. That puts it in the Top 5 of "common" planes (as in the 1940 planes can probably "out turn" it, but nobody flies them so I'm not counting them)... and I'd rate the Ki-84 as #1 in a sustained slow speed fight.
Top speed? How fast is it on the deck, that is all that really matters. I'm sure it is ~340+, which is good enough for the MA.
Roll? Not really that important, honestly. A decent pilot can negate a "roll advantage" unless it is on the order of a 6-7 second advantage in a 360 roll.
Climb (= Acceleration)... I've heard this guy is good. I don't have a bunch of experience in it (flew it a couple times in a H2H room), but from what I saw, and from what I've heard this rates up in the top tier for acceleration.
Guns? Well, once you get a Hizooka, more are kinda like overkill. It may not have the "best" firepower... but it has more than enough to kill without any problem at all with two Hispanos.
Now, does that mean anything? No, not really. For my money, the La-7 is as good as a Tempest as a fighter, but the La-7 has been free since it was introduced. So, HTC probably doesn't really care what I think about the planes, and they certainly don't use my opinions as a basis of perking planes.
I don't know if HTC will perk the Spit 16 or not, but I rather doubt it. It is a popular plane, and having a fastish Spit can't hurt the popularity of the game, since the Spit is one of the most famous planes of the war.
I also doubt that HTC will unperk what is perked currently, or follow the equally radical course of perking new planes that are free right now. I think basically the rationale for that is "Why fix what ain't broke?". HT has said in the past that they expect players to get burnt out and quit after a year (or maybe it was 2, I'm not sure). Most of the people who post on this board have been playing for longer than that. Granted, most of the people who post on this board have more "enthusiasm" for the game than the average player, but that extra enthusiasm can only keep you interested for so long. The CT has been around as an alternative for the "1945 arena" for years, and it has been deserted for years. Why? It has already been stated... people WANT to fly their 1945 planes. If they don't get to use the 1945 planes, don't play in that sandbox. HTC has to make the game fun for the lowest common denominator. 1945 planes make the game fun for them.