I really doubt that would happen given that Nagoshi-san has said that Yakuza wouldn’t feel right without Kiryu.
They took a break to make Ishin and Zero and still had Kiryu as the main character of both. I think we’ll see more stories with multiple characters like Y4, Y5, Dead Souls and Zero from here on out. Except for the spin off games of course like Kurohyou on the PSP and Ishin.
If they kicked logic to the curb and decided to make a Majima only game I’d play the hell out of it!