I kinda have to agree with this, only because of the fact that A) Captainflowers was probably the first western caster to actually make games exciting (I literally watched 20% more lcs games just because he made them watchable) and B) western casters are too focused on making stupid fart jokes and puns instead of trying to actively engage the audience and possibly have them learn something while watching the game (which is one of the reasons I kinda hope they decide to exile phreak the way they did pulse/"Saita").
Oh, and I'd heavily reccomend watching the latin american/spanish leagues if you want to see high-quality casting. One of my friends has been trying to teach me spanish so I can better understand their commentary for it (yes, I enjoy it so much that I'm willing to learn a whole new language), as they'll not just do commentary on the game and emphasize big plays but they also apparently go in depth about how each of the plays is possible, similar to what LS does in his "critique" videos only actually in game.