K/D ratio is not a measure of how good the plane is. The Finns managed that INSPITE of flying Brewsters, not because if it. They were simply much better pilots than the Russians the opposed, especially in the early 40's. The German aces also had a party on the eastern front in the early years, though in the case of the LW they really did have better planes. I also suspect that the better VVS pilots were sent to fight the Germans. Much of that changed by the end of 44' though.
I for one am not a guy to hop on any bandwagon and I love to play the Devil's Advocate. The question begs of pilot quality: Were the Finn's that good or were the Soviets that bad? I mean really, it isn't like the Finn's were at the fore front of aviation development. Training? Technology? ACM's? The RAF, Luftwaffe, USAAF, Japan, and even the Soviets can all claim a piece of that pie. Heck, even the Poles can at least stand on the PZL P.11 as an achievement. Did the Finn's get some uber training that no one else knew about? Did they dump in some super juice in the fuel tank when no one was watching? I will give the Finn's the benefit of the doubt with the k/d ratio, it is impressive. But when supposedly the Buffalo was the bottom of the barrel in the PTO, ETO, and MTO, yet do so well up north in the frigid air over Finland one has to wonder was it the Finn's that were really that good or was it is the Soviets who were really that bad??? And... just how much effort would it take for HTC to add in the version, the version we all were expecting in the first place, to be added in to AH because in EW scenarios the Brewster has every advantage over the Zekes and little needs to be said about that.
Please do not assume that I do not respect the Finnish pilots for their achievements and sacrifices in protecting their country, I hold them in nothing but the highest regards.