Yoshitoki was never meant to be important asides from being Washuu and while Tsuneyoshi's treatment is disappointing, Matsuri and Furuta fill in on their roles and what was their purpose. Plus Tsuneyoshi got his infamous SSS rate fight in shitty omake at least. Which can't be said for Tatara who's last insight was Houji and we know how that went. Ishita alluded on China operation, kept teasing about it only so in end he never delivers by killing both Tatara and Houji with zero insight about it.
Roma on another hand did had insight. She had her entire backstory slammed in one chapter. You may complain about all about her being given in just one chapter, but at least her character got completed before being killed in retarded way. Same again can't be said for neither Tatara or Houji that just got killed in retarded way after years of Ishita trying to build up hype for them and events in China.
Nagaraj's case hasn't been solved for me to even consider it based on speculation of what is most likely to happen judging by Ishita's hacking of late. Regardless of him being dead or Uta, it is clear his character as well shall be completed before being buried forever. And Ishita got soft spot for Uta, so there is that too if it is him. So again, he won't get it worse.
Kaneki is almost touché but only if he truly bit dust 100.0% without some sort of Jesus comeback. Therefor this doesn't count. For now at least.