There is a role hierarchy revision in the application. Users need to move from their existing role hierarchy to a new role hierarchy. This is going to impact Report and Dashboard folders. I want to know what all other areas will impact and I need to think before deploying a new role hierarchy with the existing user base. List view also needs to consider! what else? I want to make sure that users will continue to see what they were used to even with the new role hierarchy. The old role hierarchy needs to get deleted once the new one is in place.
Changing the role hierarchy will definitely change sharing. Make sure you review your sharing rules and recreate them for the new hierarchy. Also, as you observed, review your reports, and save them using the new hierarchy. I recommend using Save As so you still have a copy of the old reports until you're done. It is recommended that you fix sharing before moving users, as moving users and then fixing sharing may cause significant sharing locks (hours or even days in large orgs) if you move users and then implement new sharing rules. What should only take a few minutes to a few hours can easily turn into a few hours or weeks if you move the users before creating the sharing rules.