the truth is I've worked harder than them to understand the character and his matchups. most of the general gameplay problems people complain about with sfv can be overcome with practice and the game is rarely to blame for their losses, yet people will use it as a shield for their ego. Especially anyone under super diamond.
there's no real excuse (besides online issues) why, for example, your birdie shouldn't be a higher ranking when there's 2 birdies in master rank right now. Not the character or the game. you're just not working hard enough on your problems, it's that simple. you have to get your mind in the right place while you play and adopt a beginner's mindset again if you're stuck. To top it off I really just like my character, the playstyle is literally me
Short answer would be decision making. Not exactly guessing, more like reaching a level of understanding of the game, you, your character, the opponent, the opponent's character that you just seem to "know" things. That's what separates players after learning everything else.