It has an impact on plain flight performance. Your comparisons make no sense as we run into an apple vs orange situation - at least at prop BRs in Air RB.
If it would mean nothing we would not see a 262s at 7.0 whilst their actual irl opponents sit at 4.0 - 4.7 (P-51 D-30, F8F, F4U-4b, Spit F. 22 & 24 or the P-51 H-5 are post WW2 and/or never saw combat in WW 2).
I can go 930 kmph TAS in a dive in a P-47 (the 3.7 one) but as soon as i miscalculate my and the energy state of the Wyvern i lose way more energy than he does in this dive - that’s why i mentioned the safety net of 2 km alt which experienced Wyvern pilots use - this allows them to increase their speed with a slight dive - draining your energy.
So the longer you need for your dive attack the more energy you lose in this dive whilst the high speed acceleration of a Wyvern is not bad - so you need a perfect timing as your firing window becomes very small as soon you get below 2 km.
I mean i wrote above:
This was when the plane was 4.0 - the high rip speed at very high alt is even more impressive.
Same here - you need a 5.0 D-9 with enough altitude advantage as you have to get with 7-800 meters (at very high speeds) in order to hit anything with your 20 mm MG 151s - since they were nerfed in June/July last year. I mean i caught a Spit going 800 kmph on the deck with a He 162 coming in with 937 kmph out of dive - see my bug report.
Wyverns vs Spits - how often does this actually happen? Israeli Spits are the only possibility for such encounters and the 4.3 Spit is slow af for a 4.3 plane; at least on the deck - and the XP-50 is equally slow on the deck whilst has an extremely low rip speed of ~ 700 kmph TAS.
That is the difference between having an opinion and having killed several hundreds of Wyverns over the years.
I see this claim in several threads and i have zero clue why nobody tries to think about this.
Just ask yourself: When did gaijin ever removed an airspawn for a single premium aircraft? They would reduce the sales (highly unlikely) and would also indirectly admit that their BR setting policy and balancing aircraft with airspawns at lower ranks is crap (even more unlikely) and on top all Wyvern customers would be infuriated (extremely unlikely).
I disagree regarding uptiers.
I played a lot (~100) of 5.0/5.3 matches in Air RB in the last months (A7M2, Ki-84 ko, 109 G-6 and a hell of full uptiers in the B-18B) - and i saw hundreds of enemies dying to Wyverns - it doesn’t matter if we talk about 5.0 Me 264s or 5.0 Yak or 5.3 P-47 Ms, the quality of their pilots decide quite often these encounters as their early game presence.
So the basic rule (get asap above 5 km to be somehow safe from the spraying 1.200 x 20 mm attacks) is valid there too - the sole difference is imho that way more pilots are able to catch a Wyvern.