>>4887539325 chapters isn't really all that much, especially in comparison to a lot of shonen manga. I really hope it doesn't get drug out as far as others have, but to me the chapters seem pretty episodic where nothing is drawn out into multiple chapters unless it's important, and I kind of like that about it.
I'm sure more will happen soon, but I'll agree that the side characters are pretty useless for the most part. With Yukio, Rin, and Shura, it's probably to be expected that the contrast is really noticeable.