So yep, because climb is only used to calculate who gets to bounce whom, maneuverability definately should increase with speed.
No one knows the formulas, only the devs so that is impossible to answer, making things too different might destroy the model. Also i think you are making a confusion, it is not rate of turn vs radius, when you say this:
quote: it is clear that fw190 have a poor comparatively sustained rate of turn. The difference is between sustained and instantaneous. In Modern air combat for example the traditional delta wing Mirages are know for very good instantaneous turn rate and poor sustained turn rate, drag makes them loose energy fast.
FW190 could turn very quickly at high speeds, before the maneuvering would slow it down.
Thats exactly what I meant - sustained rate of turn is less important than instantaneous if the fight is not 1 vs 1 and especially if the plane happens to be faster than its opposition. There is no need to turn multiple 360s with the bandit to gain firing position - one quick turn to pull the lead, fire, and break. If you miss, someone else gets to fire it, sooner or later, engaging in a sustained maneuvering fight where energy retention and sustainable rate of turn matter more is the last resort, and real pilots without a doubt liked their lives. This is why I think, if the game uses mainly the maneuverability value in calculating who gets to shoot whom, should increase with top speed. Faster planes in typical situations also have more energy to burn.
But yeah without knowing exactly how the system, its hard to tell.