Flash was nicknamed "God" because he surpassed all of the previous bonjwas. With three MSL victories and three OSL victories, he tied NaDa's 6 accomplishments (though if you also count Proleague, WCG, or GOM Classic in this measure, Flash surpassed him). For comparison--iloveoov: 5; Jaedong: 5; sAviOr: 4; Bisu: 3; BoxeR: 3; July: 3; everybody else: 2 or less.
But what's possibly less known is just how close he was to a complete and total domination of all the records that were set before him:
- He was one map away from winning 2010 Korean Air OSL versus EffOrt, which would've made him an unprecedented 4-time OSL winner. Had he won this OSL, he would have won dual starleagues twice. The only players to have ever won dual starleagues are NaDa (2003) and Flash (later in 2010). - He was two maps away from winning 2009 NATE MSL (one of those losses was due to the infamous power loss) versus Jaedong, which would've made him an unprecedented 4-time MSL winner. - Had Flash accomplished both of the above two, he would have won all 6 starleagues in 2010. - He lost the final ace match of 2012 SK Planet Proleague Season 1 to Bisu. Had he won, he would've achieved the three-peat for KT Rolster. (For the record, no other team in Proleague has won back-to-back grand finals except KT Rolster with Flash.) - He tied iloveoov's 16 win streak in Proleague, but then lost to Dear. Had he won that map, he would have set another record. - He spent 14 months with the highest KeSPA rating (2011 Jun ~ 2012 Jul), before he was bumped off by FanTaSy in 2012 Tving OSL, who proceeded to take the #1 spot. Had Flash won that fateful series, he would have ended Brood War at the top of the ranking, and dethroned NaDa's 16-month streak (2003 Apr ~ 2004 Jul). Flash did, however, have the highest ELO peak of all time, both in total and in all three TvX matchups.
It's difficult to argue that Flash was not the Greatest Of All Time in Brood War. But had he won just seven more maps than he did, it would have been entirely indisputable.
All I see is "shoulda woulda coulda". 5/5 for making a blog pointing out your gods failures. What's next? Bisu fans making a blog on how close he was to winning OSLs?
His GOAT status is indisputable on accomplishments and win % alone, even without the choke vs Effort. True he holds the ELO records for every T matchup but he also dominated opposing races more than non-terrans (basically each of his matchups was more dominant than the best matchup of any other BW pro). Notably JD is second in ELO peaks vs all 3 races - a testament to Flash's greatness as he dominated with historically strong opposition like Fantasy/JD/Jangbi.
KT would've 3-peated too if it wasn't for that travesty of an ace map.
EPT
Flash was nicknamed "God" because he surpassed all of the previous bonjwas. With three MSL victories and three OSL victories, he tied 
Jaedong: 5; 
Bisu: 3; 
