Imagine though how clever Mitchell really was.
-The Spit was expensive and somewhat difficult to build, not a good thing if resources are scarce or there are not facilities or experienced builders. But in the end it probably was worth the effort.
The wing had the highest critical mach of any ww2 fighter, and passing beyond later models like the Spiteful.
-With 13% thickness ratio (Compared to more standard 15%) this is bound to happen, and usually in games only good features of such arrangement are modeled. From type 21 onwards the wing was different and resembled quite much that used in Tempest. The new wing caused some critique, however.
The aircraft could out-turn anything as fast as itself.
-Debatable, it is possible that in very slow speed 109 could turn tighter, but Spit could probably counter this with better turn rate if need be. It is also possible that in high speed such huge wing creates lot of drag with AoA giving some advantage to planes with higher wingloading.
The aircraft had insane ROC compared to engine power.
-"Insane" Ok, so did 109 (its main adversary).
All merits for a defensive fighter that had to go fighter-to-fighter...but that's not all...
-Holding my breath...

The aircraft was forgiving in the stall
...And for the pilot easy to fly
-More like prone to flat stall that was not possible to recover in the worst case. Dangerous enough to partly ruin the elliptic lift distribution with washout? Easy to fly due to low wing loading that's very true -and that even with bombs loaded.
The aircraft turned out to be versatile as an attacker, PR, and even naval....
-Its Naval usefulness is also debatable, I have understood that in the long run it structurally lacked the endurance needed for Naval planes. Also the landing gear arrangement is not very good for that use. I'm sure the 109T would have had the same problem in actual CV use. I'm not sure which model had the ability to carry bombs under wings. Otherwise its versatility was not really different from 109 and one hardpoint under fuselage does not make a plane versatile in my mind. In comparison 109 was not versatile, but 190 certainly was.
The aircraft could adapt to a different powerplant (That and naval, the much younger Mustang could not do)
-You mean Griffon? Why couldn't they put Griffon in P51 if they wanted?
And this is flown in 1936!
-What do you mean? The concept? It is debated if the Spit design owes to He70 from early 1930's.
I'll skip the drawbacks for now. Well there are always some...
-Sure. It's a fine aircraft and my point was not to bash it but just to point out how it may look from a bit different point of view.

-C+