I'm sorry but I can not agree with that reasoning. If its gotta be bigger, better, faster to be included then that leaves out way to many planes for me.
Funny how speed is the one paper stat that so many people focus on, yet for me "fights" never really happen at full speed 
The reason that in LW MA if you are in a slow plane and get an tactical advantage, everyone just hits the throttle and walks away from you. The speed is required to
FORCE a turn fight. When I fly the K4 every fights ends up a stall fight. Players know they're only option is to try to out turn it, because they can't out run it. When I fly a P-39, which is a better turning plane, no one turn fights, because they can all just walk a way and wave bye bye. So it's turn ability and quirky huge cannon are wasted.
I see the P-63 as the P-39Q you can't run away from. When I catch 'em in a 63, I'll still miss with that bazooka anyway. Trying is the fun. It's not a Bigger, Better, Faster Superplane