Design of the RDV application
This website/application should be used by campaign manager (authenticated users and members of an organisation), and be based on the campaign code - a data model of which is available here.
Each topics could be a different campaign, feedback categories can be used to sort feedback - not as a tag - and feedback will be associated to contact, as it's currently done in the campaign manager.
Campaign Manager must be able to check on feedback per contact and per topic, to quickly create a new topic or add a contact (either from the database of contact or by creating a one by hand).
Groups can be used to create formal and informal structures (using group type), so a campaign manager should be able to create both.
A campaign manager should only be able to access data of her own organization and a non authenticated user shouldn't be able to access any data, most of those will be notes of private conversations.