"Am I seriously suggesting the P-51D could roll faster or get a better initial or sustained turn than the 109G, and if so, which G model?"
Yes, I'm suggesting that the late Defence of the Reich Gs were sluggish old mules, a far cry from the Es and Fs, and that despite its vicious departure characteristics, the Mustang was better.
"You ask about the Battle of Britain. Aircraft performance was the deciding factor was it? If so, which types and why?"
Let's not get into the 'Hurricane was the real hero of the BoB' can of worms, but simply acknowledge that (except in negative g push-overs) the Spit I had an edge over the 109E-4. Or think about aircraft performance (especially agility) to explain the high loss rates of the Defiant and 110. Case proven, I'd have thought.
I'm not saying that aircraft agility is always the deciding factor, and didn't mention the Winter War (though I think that your claims of Finnish Air superiority are simplistic) or the Battle of Berlin.
You say that in the Pacific Japanese aircraft were highly manoeuvrable, yet lost in huge numbers?
Performance was a factor, though obviously other factors will always come into play. In the Pacific, aircraft manoeuvrability was an enormous factor in the early days (Zero vs Hurricane/P-40/Buffalo) and again later when the later, heavier Jap aircraft came up against the F6F Hellcat.
You claim that in the Korean War "the MIG-15 generally out performed the F-86E".
The handling problems and departure characteristics (to say nothing of the pilot quality, training and methods of operation) of the MiG-15 meant that it was effectively and functionally less agile than the Sabre, hard or slatted. NB that virtually every kill was a guns kill in a turning fight - go figure!
War over North Vietnam. US Air superiority. Yet VNAF aircraft have superior agility in most types they employed.
Hype apart, the VNAF performed extremely well against the USAF and the USN, until the skills of manoeuvring combat were taught to the USAF and USN. Overall, of course, the VNAF lost the war, but poor tactics and training, massive numerical inferiority etc. were the reasons. Had they had less agile aircraft, US attainment of air superiority would have been swifter and cheaper.
and as you say: "Same as above for Arab Israeli conflicts."
India - Pakistan. Pakistan gains a greater number of kills. Why? Aircraft type?
Any assessment of either Indo-Pak conflict is difficult, because all published works on the two wars rely over-heavily on over inflated PAF propaganda accounts which are of dubious veracity. However, it's noteworthy that in most engagements, the more agile aircraft usually won.
Falklands. FAA get consistent AA kills with no (?) AA losses. Why? Sea Harrier?
Sea Harrier certainly more agile than bomb- and fuel-laden Daggers and A-4s.
Your GENERAL conclusion - that the side with the FASTER aircraft TENDs to be the winning side bears little scrutiny, BTW - you need think only of the Luftwaffe at the end of the war, with 262s, 163s and Ta 152s, or the Falklands with Mach 2 Daggers against subsonic SHars.
Unless you can guarantee superiority in all other respects, giving away the advantage of better manoeuvrability is simply stupid. You say yourself that you are "not talking about individual encounters and combats", yet clearly any air campaign will be a summation of those individual combats. Go out and lose every time, and you'll lose the war. Go out in a less manoeuvrable (but otherwise equal) aircraft and you'll lose.
And in the future we can expect numerical parity (or even inferiority), enemy aircraft with superior performance, and, in some aspects superior weapons, while the growth of the upgrade market makes it entirely possible that enemy aircraft may have near-parity in sensor and systems performance. Aircraft like the Su-27 and MiG-29 may already enjoy superior very low speed high Alpha agility, so spending money to narrow that gap, and to give better manoeuvrability in other ares is essential.
Remember that when EF was being designed, the Russians had helmet-mounted cueing systems and large-angle off boresight weapons in service, while NATO did not. To have deliberately designed EF as an aircraft no more agile than the F-15 would have been short-sighted and criminally irresponsible. However, I suspect you've made up your mind....