This would be huge for us - We have a lot of pages in the menu and it would be great if it could show a count of the new records and the page could disappear when the records meet certain conditions

This would be useful. We currently rely on an overly complicated set of roles in order to do this. This then has ripple effects to make our other permissions more cumbersome to manage.

Unless we want 100 different roles, we're also severely limited in how many different permutations of user parameters we can use to influence the nav.

At present our roles are typically a combination of user type and user stage e.g. Applicant - Phase 1, Applicant - Phase 2, Staff - Phase 1, Staff - Phase 2, etc. etc. Instead of having 6-10 roles we'd like to conditionally show nav items based on fields so roles would be Applicant and Staff. Phases would be a select field.

Just ran into this issue myself. I have a layout / navigation Menu Item that is for approvals for a permissions level 3. There are lower permissions levels with their own layout. L3 has the other two permissions stacks filtered out of the Record List.

The issue I'm having is that the record lists show "No Records Found". Since the data has items in it for the other permissions level, there is not a way to filter out visible data (data is still in the field).

If I was able to have a visibility filter on the Layout / Navigation Menu Item, I could "turn off" the Level 3 tab until there is data for them to see.

Normally, this wouldn't be an issue and people could just go to that tab and if there are no records, move on. I'm rolling this Layout up to a User Layout with an Approvals tab for all approvals. This tab sees all (L1,L2, L3) approvals whether there is data or not, making it a huge list. Since there is data (just filtered based on conditions) and the Layout / Nav Item wants to be seen, the list will still be visible without a common condition to filter.

The first part of your request can be done with Roles. The second part would definitely be novel though.