The Harden story is an encouragement.
I do think this is the right choice. If you are going to build around Booker, let Book be the best Book. Don't make him change his game for others, let them change their game for him. This also establishes Book as the Alpha on the team.
If Green can make it work, great. If not, try something different. Green has the handles, speed, and athleticism to play the point and defend it. He was showing a lot of defensive improvement going into last year. He hasn't played with an offensive weapon like Book to pass to.
I could work. Maybe.