The speed differential is not as lopsided and there are more than two planes that are competitive. The F-86 would be used for far more than 50% of the flights. If it was like the MA it would basically be F-86s vs F-86s. If it were done on historical sides it would be a bunch of F-86s looking for the one schmuck who upped a MiG-15.
I call the schmuck slot! EAT 37MM!
Seriously, though, I disagree with your assertion that it would be all F-86's versus F-86's. Sure, some of it would be that way, just as there's lots of folks in the MA's now who fly Spit 16's, LA-7's, and the like exclusively. But there's also a HUGE number of pilots who don't want to just hold alt, then dive down picking everything in sight, then run away and do it again. Those are the folks that would figure out a way to make the underrated planes be competitive with the higher-performance ones, just as they do now in P-40's, P-39's, Spit and Hurri I's, and so forth. The folks who will turn on a diving P-51 in a Mossie with an engine out and half the plane shot off, and still kick his butt. I think you underestimate the stubbornness of many of the pilots here, who stick to their favorite planes no matter what the enemies are doing, and get lots of kills and have good fights and lots of fun, which is what the game is about, at least to me.
All that being said, I would only like to see a Korea arena AFTER we get the WWII planeset properly done, as there are still some decent-sized gaps there. (And I want my P-40N and P-63!)