Some intellectuals would be attracted to principles which aren't there in PRC and might not go but not everyone. Like OP mentioned, for some creating an impact at an scale that is possible inside China might be attractive enough. Also, as long as you toe the CCP line I doubt they would be making life difficult for you. At worst, you will be free to travel within China and possibly live a very comfortable life there. I can totally see mainland Chinese companies poaching talent(specially overseas Chinese) in areas they lack by giving very good opportunities.
The way China has developed and the growth potential still there, I can totally see Chinese expats moving back there.
The problem is that you can’t trust any CCP promise when there is no rule of law. What’s to stop them from paying you less than you earned abroad and simply denying you an exit visa once you arrive? They would probably treat you well at first so that you can tell your friends still overseas that the deal is good. But once they have their talent then they don’t have a reason to keep treating you like a king.
The way China has developed and the growth potential still there, I can totally see Chinese expats moving back there.