I don't think it's reasonable to expect the process to define how a team should confront the problems found in a retrospective. Those project and team specific problems are likely to be unique and giving the team the framework to choose the best course of action is likely to more effective than some prescriptive process that says "If A then do B".

It also wasn't meant to provide guidance on how teams should improve themselves, that's up to the team to choose the best route to get there. It excels at enabling the team to make those decisions for themselves.