Imo speed is the single most important factor for a plane, faster planes can always dictate the terms and simply run for it if its getting too hot.
But why is this "myth" about the überness of slow turner still around?
It is
Flying the tempest in January, I was able to escape from a lot of gangs because I could simply run away from all of them. I didn't get low n slow, and I used the plane for what it does best. I was capable of staying alive because I could get away from trouble without having to worry too much about other planes catching me. This is kind of a boring way to fly, but in real life you would be very happy about it.
A TnB plane cannot get away from a gang unless you out turn a 5-1 and win the fight. You will have to be very good defensively and know advanced ACM to be able to win the fight Vs a group of cons. In a 1v1 fight, if I'm in a P38 Vs a Zeke, if I get slow against it, it will win every time if I cannot dive away. If I don't use my E and speed wisely, I will be an easy kill. Now if it was the Zeke Vs 5 P38s, it would be very difficult for the Zeke to gain any type of advantage.
That's why you don't see very many #1 pilots in zekes and Fm2 because they are out matched and getting ganged in them will happen a lot. No matter how good your SA is, you will die simply because you will have a very hard time escaping multiple con situations.