Speed and maneuverability are almost diametrically opposed in WWII air combat fighters. The faster the plane the lower its sustained turn-rate and vice-versa. I call speed fighters "initiative" fighters, because that's really what speed is, the potential for tactical and strategic initiative. The ability to get and maintain the initiative is crucial in air combat. At its core speed is actually an offensive quality. It affords the fighter the opportunity to attack with a high rate of closure with relative impunity assuming the advantage can be maintained. Superior maneuverability is defensive at its core, affording the opportunity to turn at a rate that spoils a potential gun solution of a plane that cannot match that turn-rate. The only time turn-rate can be offensive is if the enemy has already decided to turn with you and you are able to gain angles for a shot with it. If he decides not to turn with you, turn-rate can only serve a defensive purpose.
The ability to engage and disengage at will is an extremely powerful tool for the thinking fighter pilot. Maintaining the initiative in this way is difficult in complex engagements, but when done properly, in concert with good SA and gunnery, it's magical. The ability to turn well is extremely important in isolated encounters, but in a complex engagements against equally skilled foes it becomes largely defensive and relatively unimportant. The only way maneuverability is going to allow you to disengage is if you destroy all the enemy that choose to engage you, which is obviously impractical in most complex engagements.
If you think of speed as initiative you quickly realize that it allows you to choose when, if, where and how a fight occurs. Even a fast plane that is "egressing" actually has the initiative, he is effectively pulling the chasers around by the nose, they are the tail and he is the dog. The problem with initiative fighters in the MA is a lot of people use them poorly and misunderstand how to fully exploit the initiative. Exploiting the initiative to maximum effectiveness is very cerebral and nuanced, not nearly as straightforward and mechanical as latching onto someone's 6 with a Zeke and plugging away until one of you dies. A lot of people use initiative fighters who really don't have the disposition for it or sufficient understanding of it, this leads to the "timidity" factor observed in the MA and their relative ineffectiveness.
