Lol no, that might be fine if you're talking about your run-of-the-mill junkballers, but it's not the case when you're talking about elite pitchers like Ryu and Kyle Hendricks. Their slow stuff isn't for show, they're legitimately excellent pitches that tunnel very well with one another and keep hitters off-balance for entire games. Ryu's problem early on has been that his command of his pitches hasn't been to his usual standards, not that his stuff is falling flat and hitters are sitting on slow stuff. You can tell by the number of strikeouts he has and the soft contact he was inducing the first couple of innings that his stuff isn't the problem, but rather his location.