How can Flows be centrally managed for an organization?
For Flows to be useful in an organization setting, a team of people needs to be able to access and manage and curate Flows. It simply will not do to have these be associated with personal accounts, even if you can publish them and have them be re-used by others.
The SharePoint Workflow management system gives an example: Site Designers (or any with appropriate permissions) could access workflows and manage them.
Flows needs something similar. It needs to allow Groups of people to have access to sets of Flows to be used for the organization (e.g., IT Developers/Admins, Sales Department Flows, Project Alpha Team Flows, O365 Group Flows, etc).
It would be great for Admins at various levels to have oversight access to ALL Flows created by Groups that they are responsible for; Sites (SharePoint) or Accounts (Outlook) or Entities (CRM) etc. that they are responsible for.
For security, Admins should also be able to see any Flows that hit their sites -- access the APIs -- at least to be able to manage permissions of those, seeing what account they are accessing under and being able to manage permission of that account or directly set a block on the Flow, even a temporary restriction (I could imagine a Flow caught in a Loop that causes a mess on a site with Item Creation, or email spamming, or even chewing up resources to be an effective Denial Of Service).
For business use, even at the small business level, Flows will remain a desired but unmanageable feature without these controls.