With J - man it wasn't to big of a shock b/c of his age and what he has already acomplished for Konoha , and his big battle with Pain ... his death was more complete and was "eased" into everyones mind I think. Another thing is you added Kakashi among the important that died and you cant really say that just yet , there is a chance he's still alive untill is says Kakshi is dead and they have a funeral for him ... same with Hinata for that mater. Kakashi's battle was to short and I feel that something is off with the whole Kakashi death senario. Same with Hinata though yes it could be the same in real life .. one moment someone is there and the next bam taken down by something very quick. However in this manga important ppl tend to have a long drawn out " go out with a bang " ending. Endings that leave you with a sense of loss but satisfaction that their ending was a good one. The 3rds for example , Grandma Chiyos , Zabuzas, Hakus , Jiraya's and even Itachi's ending were all great endings for their characters. Kakahi's ... nah, and neither was Hinata's though she wasn't as big as those other ones. One thing i've learned from reading Naruto is that you don't believe something " is " untill Kishi has said so in the manga. He's always got a suprise ready to shock everyone with. Also Kakahi's " possible " death and Hinata's as well as Pain V.S Naruto , Sasuke VS Itachi , Sauske VS Deidra , Sauske V.S . Killer Bee , Danzo , Orochimaru's death / battle with Sauske and Itachi and many other things tie in with the title " Shippuuden" or Hurricane which to me means lots of things going on at once and happening all so fast ... so much so that in the end you are suprised , Confussed , Shocked and not sure what to believe or expect next.