Oh, they are very important, no doubt, but I still place speed as the most important. Obviously there are minimum values for the other two to be useful.
I will say, I am not sure the Spit XIV is a better turn fighter than the P-47M. It probably is, but I am not certain. The Spits VIII and XVI are certainly better turn fighters though.
The SpitXIV will sustain a better rate and radius no doubt, but when it comes back to just hauling back on the stick for deflection without squirrely nose-wagging??? Yeah, perhaps the SpitXIV should be unperked on a trial basis if we're stuck with that trait.
Speed is not the most important in the game. The most popular plane in the game is *not* the fastest unperked. The second most popular plane in the game (really the most popular if you consider the SpitXVI, SpitVIII, and SpitIX in aggregrate) is nowhere near the fastest. The D9 is nowhere near the most popular in the game, despite being nearly the fastest, and quite good in every single trait *except* turn. The ACM/gunnery problem of getting a solution on a much more maneuverable bandit who knows I'm there is the toughest offensive problem I face.
Its an interesting paradox, turning ability is what lessens the problem most on offense, and speed offers the easiest defense, and with most planes you trade one for another. When one only has one life to live, then top speed over all obviously, but in a "game", getting four kills and then dying...and reupping to do it again and again, is perfectly acceptable, and arguably alot more fun for most people than flying a fast brick conservatively and getting a kill every now and again.