Here is what trust level 4 can do, for context:
Trust Level 4 – Leader
Leaders are regulars who have been around forever and seen everything. They set a positive example for the community through their actions and their posts. If you need advice, these are the folks you turn to first, and they’ve earned the highest level of community trust, such that they are almost moderators within the community already.
Get to trust level 4 by…
- Manual promotion by staff only
Users at trust level 4 can…
- Edit all posts
- Pin/unpin topic
- Close topics
- Archive topics
- Make topics unlisted
- Split and merge topics
- Reset topic bump date
- Daily like, edit, and flag limits increased by 3×
- Any TL4 flag cast on any post immediately takes effect and hides the target post
- Can send personal messages to an email address
They can still perform moderation duties, but they don’t handle the review queue.
You can set the user’s trust level to 4, and remove their moderation. And you can use what ondrej mentioned to give them a badge and title.