ability for site admins to manage tags (instead of having to directly access the database to change any of them)
presumably this implies a site settings page for admins
presumably this also implies a way to determine who "admins" are. probably just a list, modifiable by admins. or maybe there is an "owner" who can appoint admins. or something.
(possibly) ability to have more style options on tags as well as just text and background colour
when we have multiple (sub)forums, then there should be per-forum tags (ie rules about what tags are usable in what forums). new tags for a subforum should then also be creatable by the "admins" of that subforum.
this implies some kind of per-forum moderation system, which i haven't fully thought through yet.
if we have nested subforums, then there should probably be an option to make tags inheritable and not inheritable, perhaps per-tag.
(or you could just recreate tags you want to inherit tbh)