collins On second thought, I think a tag-based solution would probably be about as equal in work to an extension. At least if I understand your question correctly. I guess the only real question is, will your community staff be picking out topics to make visible, or is this up to the members?
If the staff, then here's my solution for you. Let me illustrate using devflarum (full images here):
You set up at least two secondary tags. I've called mine Featured and Not Featured to make it simple. Then you set your permissions like this:
So normal users will see this when they go to start a new discussion (remember we're requiring at least 1 primary and 1 secondary tag):
Staff will see this:
So then let's say you have a tag where members have posted under the Not Featured secondary tag (because that's all they're allowed to do. Your All Discussions page will look like this:
And the tag page will look like this:
Your staff will go to edit tags and switch from Not Featured to Featured:
And voila! You have this discussion appearing on the All Discussions page, with none of the others:
That's going to be about equivalent work for your staff as having an extension made that does this by clicking a button. And it's even more versatile because if you want to apply special permissions to those Featured discussions now, you have a tag to work with and modify its permissions.