YOu should think about the time line. Izumi died, and Kurono got attacked that same day. The team tried to help him, but he got killed and the vamps got in the room. Then there was the Nuri mission and immediately after it was the rome mission.
A few days after before they could do another mission and score points to revive someone, katastrophe hit and the aliens arrived.
There was simply no chance to get him back, unless Katou would've revived him instead of Kurono.
And I'm not sure anyone would've brought him back. Kurono wouldn't have asked someone to do it, like he did with Nishi. He didn't like Nishi, but believed he could give them information. But he pretty much hates Izumi. He killed Tae after all.
From the rest of the team, nobody really knew Izumi. They knew he was strong, but in no way a team player. And if Cherry told the others that it was Izumi that killed them all, or the others already knew, they wouldn't bring him back.
"For Feanor was made the mightiest in all parts of body and mind, in valour, in endurance, in beauty, in understanding, in skill, in strength and subtlety alike, of all the Children of Illuvatar, and a bright flame was in him"