the upper final is kind of redundant in this format. it means, a team can fuck up early in the competition and still win the masters. in the grand finals there would be 1 team that went undeafeated and 1 team that already lost a game. so, it's unfair to the undefeated team as it disregards their form up until that moment. but, gives a second shot to the other team based on nothing. in NA, it was just seeding so not a big deal, but in masters the stakes are higher.
fluke is not a good enough excuse to lose. and you can use that excuse in grand finals too. what if the Guard win over Optic was a fluke (i'm not saying it was)? and to reach upper finals you need to beat 2 of the best teams and to win upper finals you have to beat the best team from the opposite side of the bracket. all 3 games in a row can't just be a fluke.
"to reach upper finals you have to beat 2 of the best teams" - not necessarily true depending on groups.
dont forget that whoever makes the lower bracket run has to beat the same teams the upper bracket runner beats as well. its a better way to properly rank the teams in the tournament. vct korea had a single elim tourney and thus the second best team in KR (TNL) did not get to go to Berlin for Masters because they ended up getting an unlucky draw versus VS.
single elim means anyone can just go win depending on their luck in groups. double elim proves that you deserve your spot at GF and it wasnt a lucky sequence of teams.
also statistically double elim is better.
Double elim ensures that the best 2 teams make grand finals, regardless of seeding. Last years Iceland is a perfect example of this. Sentinels and Fnatic played in round 1, and met each other again in the grand finals. Imagine if it was single elim: Fnatic, the second best team in the tournament, gets knocked out almost immediately, and the grand finals is Sentinels stomping Nuturn.
Also, if teams are going to get byes to playoffs, single elim just doesnt work. There should be no situation where a team only plays 1 match and goes home.
those were seeding games, but imagine if it was masters. Optic already beat Guard once but they still need to beat them again to win? Guard fucked up and lost a game but, Optic didn't. but at the end they have equal chance at winning the tournament. that's why it's unfair to the undefeated team as they can't flop in the last day where the team who already lost once still gets another shot at glory. that imo, is undeserved when they stakes are higher and not just seeding games.