Let's say the pony is undermodeled.. just for the sake of this discussion. I think were you increase the turn performance of the pony very much it would become an uber ride. Each plane needs to have some balance to it.
I personally believe the pony out turns a jug in the real world but only because of what I've read. Even so, I'd hate to have any plane clearly dominate the rest of the plane set. A pony that turned sigificantly better than our current modeling would be such a plane, IMHO.
WTG
I believe you are wrong here Steve. The point is to have aircraft that conform to their real performance as much as possible. If that means the P-51D would perform so well that it would require a light perk price, so be it.
It would never be a super-plane anyway. It would still be out-turned and out-climbed by the Spixteen. The La7 would still be faster in the weeds. The 109s would still out-climb and out-turn it sustained. The Jug would still have 2 more guns, roll better, and absorb punishment better. The F4U-4 would still out-everything the Pony.