If he comes back for DOA6 I'll have mixed feelings. I could see there being another timeskip because Marie and Honoka exist.
He still with Valhalla studios i think. But he needs to come back so that the cleansing of the thots can begin.
Within the first 6 seconds of DOA6 Story mode with our boy Itagaki, Marie Rose is fired and leaves to go elsewhere and Honoka is killed by Raidou.