I think the answer is “it depends on your community.”
The Discourse philosophy is that trusted members of the community help curate the space – pick up trash via flags, organize topics and categories via TL3 editing, put up helpful clarifying signs in the site feedback category, etc.
The general idea is that the community helps organize itself. If this isn’t what you want, there are site settings as @falco noted:
trusted users can edit others
Allow users with high trust levels to edit content from other users
That one is specific to editing, so it would disable the TL3 ability to edit topic title and category.
What are you doing? Is the SEO so important to your forum? Did you try to talk to your regulars- they might be unaware of the problem.
I still cringe if I have to read trough a longer thread/topic finding out that it already was closed or totally misplaced by category and title.
In the end the rigor of the answer of the owner reduced my activity in the forum quite a bit in the last six month. Do not forget regular contributors might be what is a worth you can not easily replace