Its also called performance. If the performance levels were close there could be room for discussion but they are not close. If you want to look statistically then it needs to be undertood that Bothams downside of his career is included whereas Flintoff has not reached that stage and statistically he is weighted towards the peak of his career.
Also, if it just from eyeball analysis (I also have seen them both) then Botham was one of the best swing bowlers the world has seen and his big hitting often hid the fact that he was one of the better technical English batsmen of his generation.
I started to list the list the 1000 reasons why Botham is superior, then realised that there was not much point. Irreconcilable differences of opinion I guess.
I certainly would not coach it that way. It worked for him though and there is a growing body of thought that believes it is a more relaxed position and less 'braced'. People also think it is easier to take the hands both up and down from there.
I dont coach the hands on knees style, but there are its advocaats.
Im certainly not trying to change your view and obviously I respect your right to have it. I just think differently and Im just putting my POV across.
EDIT- If we are talking ODIs then I agree that Flintoff is a different class. Also captaincy.