Light was a terran player known for his extremely sound mechanics, having a knack for coming back from an early game deficit, absurdly powerful abilities versus the zerg race, and being the mechanics-reliant alter-ego to the other MBC Game HERO terran ace, Sea, who was more known for his smart decision making.
Now, there are no accurate ways to assess sheer mechanics, but eAPM is one method of knowing how fast a player is able to play. Notice some of the eAPM figures of players known for their mechanics during their professional years.
Bisu: eAPM range circa 2009 (224 ~252)
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http://www.ygosu.com/community/st/622651
Jaedong: eAPM range circa 2009 ~ 2010 (231 ~ 268)
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http://www.ygosu.com/community/st/887178
Flash: eAPM range circa 2010 (201 ~ 235)
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http://www.ygosu.com/community/real_article/st/247377/?page=0&frombest=Y
Now, the eAPM range of Light is much harder to find (not from a word of mouth, figures with replays as proof), but here's a bunch of eAPM of various professionals, with Light having one game with an eAPM of 251, and found a replay from 2008 with an eAPM of 269.
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http://www.ygosu.com/community/?bid=st&idx=422464
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http://www.ygosu.com/replay/?s_cate=all&idx=48103
Now, as you can see, almost every single player out there who is known for excellent mechanics and having a high octane style of play is in possession of very high eAPM records. Of course, having a high eAPM alone doesn't mean much by itself, but it's one method of differentiating the stylistic tendencies of various players.
Being fast doesn't equate to having good mechanics, but it does show that you generally have a greater ability to play high-eAPM-requiring playstyles such as SK Terran, than those who have relatively lower eAPM numbers.
For example, I don't think we can find many instances of someone who is known for their excellent bionic play from start to finish (not just being good at small scale skirmishes, but good army movement, good unit production from the barracks, as well as sound vessel management), having an eAPM way below 200.
Light, in my opinion, was in possession of some of the best hardware of any professional player, if you made the game just about pure execution, and not decision making. This was an opinion that was solidified after I watched Flash's opinion on Light as a player while being interviewed.
Flash once said that Light was like a machine, a player who was unmatched in his ability within very specific confines
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Assuming the kind of categorization we put Light under is true, and he is someone who is extremely reliant on his basics during the game, rather than being meticulous with his pre-game preparation, or having an excellent read for the enemy player, the kind of tournaments Light will excel in can be summed up in one sentence.
Lack of preparation.
If you are someone who can be broken down strategically, and be abused not with game fundamentals, but in almost every other aspect of the game, the stage you will flourish under will be the kind that provides minimum preparation, whilst playing a lot of players in a short span of time.
Enter Shinhan 2010 Winners League.
http://www.teamliquid.net/tlpd/korean/leagues/410_Shinhan_2010_Winners_League/player_stats#tblt-717-1-2-DESC
Before the format of the tournament was changed in Shinhan 2010/2011 ProLeague, where you got to play a total of 18 rounds instead of the previous 11 rounds of regular Winners League schedule (providing a theoretical cap of 28 more opportunities to get more wins for a player than the seasons before), Light was the all-time record holder of the most number of wins gained in a single season of the Winners League.
Light managed to get more number of wins than Flash playing at his absolute best (although to be fair, Flash did have a much higher win rate, and ended up winning the entire tournament for his team). In fact, only Light and Flash managed to get over 20 victories over the course of the Winners League season, overshadowing the rest of the field.
Light was one of four players in history who managed to have three All-Kill performances within a single season, and the first player to have a back-to-back All-Kill streaks. Remember Flash's most memorable Winners League performance when he broke down the three guards of SK Telecom T1, Bisu, FanTaSy, and BeSt, in succession to win the match for his team? Flash was able to break down the fearsome "Do-Taek-Myung" ace combination of SK Telecom T1, something a few proved they were capable of doing throughout history.
Do-Taek-Myung, one of the most formidable trios in ProLeague history, and the main reason for the re-emergence of SK Telecom T1 as a powerhouse in the ProLeague
Light did exactly that, taking down the entire SK Telecom T1 empire without having to resort to his favourite match-up of terran-versus-zerg even once.
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As one could expect from Light, he went undefeated against the zerg race for the entire duration of the tournament, as well as racking up the most number of victories against zerg players with eleven victories, a notch above the next player with the most number of victories, Jaedong, had only had eight victories.
Now we could write a whole blog drooling all over Light's artful terran-versus-zerg abilities, especially within the confines of sheer fundamentals, but this won't be the blog to do so. I'll just finish this piece with the best streak Light ever had against the zerg race, which includes some of the games that he played in Shinhan 2010 Winners League.
http://www.teamliquid.net/tlpd/details.php?section=korean&type=players&id=109&part=games&vs=Z&league=any&map=any&from_year=2010&from_month=1&from_day=16&to_year=2010&to_month=8&to_day=11&action=Update
The only winning streak in history that outclasses this insane record is iloveoov's streak when he had broken the matrix with his meta-game advancements.
http://www.teamliquid.net/tlpd/details.php?section=korean&type=players&id=5&part=games&vs=Z&league=any&map=any&from_year=2003&from_month=4&from_day=16&to_year=2004&to_month=7&to_day=1&action=Update
Light's streak versus the zerg race towers above the recods of some of the most extra-ordinary terran-versus-zerg specialists in history. For example, this is Flash's best ever streak versus the zerg race.
http://www.teamliquid.net/tlpd/details.php?section=korean&type=players&id=424&part=games&vs=Z&league=any&map=any&from_year=2011&from_month=7&from_day=13&to_year=2012&to_month=7&to_day=23&action=Update
GoRush: "Professional zerg players will agree with me on this matter, Light was the scariest bionic player to face as a zerg."
I always had a soft spot for Light, because I respected his abilities versus the zerg race, and his mechanical prowess as a player. He was one of my favourite terran players of the modern era, and I never raged against his victories against the zerg race (no matter how hard I supported the zerg players), because his victories didn't seem "cheap" or "unfair" in my eyes. Quite an odd metric to like a player, but I personally believe that if every player had a gentlemen's agreement to rely only on their fundamentals, and confine the boundaries of this e-Sports to soley the real-time aspect of this great real-time strategy game, Light would have been one of the greatest players of the modern era.