Did you watch the whole video? At 1:00 is the difference : engine off. This is why guys like Skyyr or StarFox shut they engine off briefly 'at the top'. What does not look right to me effect the pop forces have on the FM while at idle. One/or all of these 4 forces are way too strong and create the weird nose wobble as the stall is 'clean' when the engine is off. Dude, I don't have a PHD in aerodynamics, nor did I stalled a real life Spitfire or P47. The closest I have is a high torque single engine experience. I currently fly a 1,600HP turboprop with the power to weight ratio of a P51 and never ever on excessive nose high power to idle stalls did anything like the AH power to idle stall happens.
I encourage you to take a Spitfire and go do the manoeuvers I mentioned above and see what your dad thinks. To me HiTech probably has the best raw fight model in the industry and I cannot even begin to comprehend how he makes it happen, but there are still areas that stand as non convincing.