^^The "casual" way in which you just put up "now, he should die" sent some shivers down my spine. (Private Joke "Zetsubou Shita! This forum that casually marks cool characters for death ore ni zetsubou shita!!!").
I don't really have anything to add to what teiohx said - HS does take up a lot of character space, and having him and kurono/izumi back would make the story too character intensive. Remember how we have been asking where the hell is HS for the last ten chapters or so? Just think about how messy things would get if we were waiting on Kurono/Izumi to make an entrance as well... not to mention da L337 c4mp3r Mr N1sh1.
^I second M_Y. Anzu dying, Katou getting almost/completely wrecked and HS butting in at the last moment are all things that were mentioned here and there in this forum. Of course, it's not bad - the way oku presented it all is just epic (buildings going boom, HS's slicing action is suberbly drawn, etc), but event wise I was expecting a bit more. I dunno, everyone gets their asses kicked and in the end HS soloes Nuri down his last life, using nano's or something. Or he turns Katou into a vampire to save him, and they beat Nuri together... etc, etc