A tournament with 253 entrants and a general lack of top players isn't really a major. Who did Marss beat to win? In top 48, Engine (who I don't know who it is), yeti, Cosmos (barely), Maister (barely), and then Cosmos again. The most notable players who attended the tournament were Cosmos, Marss, Seth, yeti, ESAM, Ned, Maister, MVD, and DarkShad, hardly a major.
OrionStats lists Collision as a Major and Full Bloom 5 as a Super Regional,
https://docs.google.com/spreadsheets/d/1AJs-mj5TTdkmkl7nhj4twJymVPTLTUdT0MBToL1cxDs/edit#gid=0.
Edit: I do believe ZSS is high tier though, and Marss is an incredibly skilled player as well.
Maister believes that Mr. Game & Watch doesn't have any really bad MUs, and that his worst matchups are Slight Advantage, those being: Squirtle, Mega Man, Ike, Chrom, Cloud, Lucina, Meta Knight, Olimar, and Zero Suit Samus. He also believes that G&W goes even with some notable characters like Pichu, Palutena, Link, Shulk, Peach/Daisy, Pokémon Trainer, Greninja, Link, Roy, and Wolf, and that he beats Fox, Inkling, Young Link, Mario, Pikachu, and Wario (and others, of course, but those are the most notable).
Oh, and Snake is a "Big Advantage", he claims. So he's fairly optimistic about Mr. Game & Watch. He might be too optimistic, but Maister's MU chart makes him look really solid.
Which MUs do you think are "really bad"?