The first game without him is great, and they announced more Yakuza games that look promising. These games are made by hundreds or thousands of people, there won't be a huge change.
There's nothing over or any special deal with anyone.
Sega simply said they want to focus less on exclusives and go more for a more global market: releasing in more platforms and releasing worldwide, with a stronger effort in localization (something non-English speakers missed in the west for games like the Yakuza and Persona series). They will also bet more on movies, resurrecting more classic IPs and making AAA 'supergames'. The only reason is that -like any company- they want to make more money and improve their financials, which aren't stellar.
Meaning that future Yakuza, Bayonetta, Persona, etc. titles pretty likely will be multiplatform.