Using the name Curator connotes content specialists such as the curators in zoos, museums and cultural collections. I don't know if that is the deliberate intention but it does remind me of the request for a category-specific moderator which is also looking to have something similar to curated categories.
This looks like an opportunity to make removing TL4 from the trust system an early phase of implementing category-specific moderation. Without a specific focus like that I can't see that, as @sam points out, it is worthwhile doing any more than changing the TL4 name and separating it from the trust system in the documents. It's not like there is any new functionality coming with the name change. I also doubt that there is any rationale for making it an additional staff group - but some of the staff might have a different view on this.
I also understand that category-specific moderation is not being implemented because nobody has come forward to fund it. It seems to be a popular request, a logical improvement for Discourse, and now justifies removing TL4 internally from the trust system.
P.S. Although removing TL4 from the trust system is probably not required unless TL4 does have staff status.