Everyone manages their own lists, having a single person manage the lists would probably be a micromanagement nightmare for both the manager and the employees.
We all have visibility over all the lists so if we feel anyone has prioritisation wrong we just discuss it and the person will re-prioritise if it's deemed necessary.
Note that we still use other task systems to manage overall priorities, for development we use Jira and that's the single source of truth for development prioritisation. The Trello lists are for short term personal prioritisation and are very malleable, and encompass personal tasks that one would work through.
We all have visibility over all the lists so if we feel anyone has prioritisation wrong we just discuss it and the person will re-prioritise if it's deemed necessary.
Note that we still use other task systems to manage overall priorities, for development we use Jira and that's the single source of truth for development prioritisation. The Trello lists are for short term personal prioritisation and are very malleable, and encompass personal tasks that one would work through.