Not necessarily. There's no hard and fast rule about these things in studios. For example, when Obsidian was working on Stormlands, the big RPG for MS which got canned, JE Sawyer was the director. It was based on ideas he and Avellone proposed at the time iirc. After it was cancelled Sawyer went on to launch the Pillars of Eternity IP. Later the ideas they had for Stormlands were revived to be used in Tyranny - a game that neither Sawyer nor Avellone had any part in.
So if they wanted to reuse some ideas from Scalebound in Astral Chain, and Kamiya says "yeah that would be cool", it doesn't mean he would want to direct the game himself. Especially when it's someone else's project now.
Oh absolutely, and that is a great example of ideas carrying over under different people. I was just under the impression that the idea of Scalebound was kind of Kamiya's baby, and if there were another game that carried over those ideas in a capacity that would be the best they could given the opportunities that existed, Kamiya would maybe want to keep control of his baby, even in another form.
Then again, I am ignorant of tons of things that could contribute to this, like Kamiya having a change of heart after the MS fallout, him feeling confident in passing off those design elements to folks he trusts, a change in the way the studio approached things, how Platinum's realtionship with Nintendo evolved, etc.