KC Cup is coming soon, and I just want to remind you that the most used decks never do well in KC Cup. Cyber Angel era, they were countered by econ take, Massivemorph, and also Dkayed's Ninja deck which made him top global. Sylvans era, they were countered by Spellbooks. Fur Hire era, they were countered by Vampires. Balance Heroes era, they were countered by Silent Magician. And the upcoming KC Cup, which will be Koa'ki Meiru era, you already know what deck would counter them
The actual reason why the most used deck can't do well in big events is because they have to face so many mirror match. 50:50 chance in mirror match and almost guaranteed lose against specific counter deck makes them only gain 20k - 30k DP at max
Last kc cup I played around 100 games with 35k DPs and around 67 % win rate, I used geargias and Amazoness control, yeah the deck you play matters and kc cup shifts happen from time to time but I swear the most important things are patience, focusing on evey duel and playing many games.
Buster Blader would obviously take advantage of so many Koa'ki Meiru players in the next KC Cup. Unless Wall negates the fusion spell, they have no chance against Buster Blader since Maximus is a Dragon
the most played deck will most often not do so well because it encounters a lot of mirror matches. in some case mirror match or not, it doesn't matter but then with decks like sylvans going second in the mirror is devastating and same can be said for koaki when going first, not to mention that getting a high place in kc cup requires multiple decks and meta adapting. 1 deck gets you nowhere