for the players currently still in gsl, the player with the highest win rate overall is DRG with an incredible 68.4% (however, he only has a total of 95 games). so if you say the sample size isn't big enough and want at least 100 games, the next is MVP with an overall win rate of 67% in 188 games. after that is Nestea with 66.7% in 153 games, Taeja (included are his code a matches of course) with 63.7% in 237 games, MMA with 61.5% in 135 games, and Jjaki with 61.2% in 129 games. these are the only players i found with a win rate over 61% and a minimum of 100 games played.
now lets head over to the international database where these gsl players play in a wide variety of tournaments with many different foreigners including other koreans. the player with the highest overall win rate with at least 100 games played is, once again, MVP with a staggering win rate of 73.2% in 179 games. next in line is Marinekingprime with 72% in 293 games, MMA with a 71.9% in 153 games, and MC with a 70.9% win rate in 309 games. practially every korean in the international database has a win rate above 61%, which only a select few players have in the gsl.
if you look at the top foriegners win rates, the only people who break 61% are Stepano with a WR of 67.5%, Nerchio with 66.6%, Naniwa with 64.5%, Sen with 62.8%, and Huk with 62.6%. Other popular non koreans include Idra with a WR of 59.9% and Thorzain with 59.8%.
All of these guys except Stepano and Nerchio have gone to korea to compete in GSL, and none of them made it past the code s round of 8 except Huk (maybe naniwa will this coming season).
TLDR? then go read cuz its mostly numbers... jkjk. but yes, top foreigners can compete and even take games off of top koreans. that does not mean they are better. the definition of a champion is someone who can constantly win and these koreans prove this by basically winning every sc2 tournament on this planet. i feel the only non korean who can be put in the level of the s class koreans is stepano, given his 67.5 win rate. thoughts?