Well I think it's clear that some planes were better then others in real life. There is a reason why the RAF replaced it's Spitfire Mk I's with Mk II's, and those with Mk V's, and those with Mk IX's etc. Airplanes got faster, their service ceilings increased, range increased, ordanance increased, etc. throughout the war.
If you try to compare them all on a level playing field, only a few of the late war monsters will stand out, and the rest will seem like total wastes of resources. Why did the RAF build anything else when the had Tempests? Why did the Russians build so many fighters that weren't LA-7s? Rome wasn't built in a day, and these planes weren't designed from scratch - they were the result of years of wartime development and experience. However, most of WWII was fought before 1945. In fact, half of it was fought before 1942.

If you look at any of the fighters in their historical context, they make a lot more sense. Take the P-47 you mentioned. The earliest model we have is a D-11, it would have seen service in early 1944 flying escort missions for 8th Air Force bombers. This would have meant flying at 20-30,000ft and fighting Bf109G-6's, Bf110G's, and Fw190A's. In this environment, the P-47D is a very comepetetive fighter. But when you start flying it at 10,000ft and below, against the best 1945 had to offer, it seems a little weak.