Yes, but here's the thing: Nothing Grant Morrison has done precludes paper-headed vampires, er, I mean Japanese superhero types, from showing up in the future. In fact, he's added to the number of such characters in existence at DC with his creation of Big Science Action, who do conform to Japanese superhero types. The Super Young Team weren't pre-existing Japanese superheroes who he Westernized. Their creation doesn't take away the number of Japanese-style superheroes at DC, or make it harder for some writer in the future to create a Japanese-style superhero if s/he is so inclined.
What bothers me, I guess, is the attitude that if you're going to create a Japanese superhero, you have to make him conform to Japanese character conventions, that that's the only way to do it and anything else is wrong. I'm of Chinese descent. While China doesn't have nearly as much in the way of superhero-ish character as Japan (as far as I know), I know that if DC were to create a Chinese superhero, I'd far rather see him be a Western-style superhero than someone based off of the Monkey King. Because the latter type of character I can and do already see in fiction. What I don't get to see, much as I want to, is people like me wearing cape-and-spandex. And it annoys me that if such a character were to appear, folks are going to complaining, as this post and its comments evidence.