My two top wishlist leftover items in that regard are
1. Marking whether a comment requests changes or not. This is of course straight out of GitHub, but I think their flow better matches what I found to be happening a in a lot of changes. I see such states for a Code review of a MR: Changes approved, Reviewer requests changes, reviewer leaves feedback (like "nice implementation", "good refactor", "minor: maybe you can refactor this?"). The last one is the most blurry in the GitLab approach since the way we can solve it is by starting a comment thread that is not resolved and approving a MR at the same time but it feels clunky. Maybe they can take a page out of GitHub's book.
2. Personal slack notifications. I would love to have first-party support for the notification system around MR, MR Comments, Being assigned, pipeline failing that messages me privately on slack. Jira recently had a revamp in their slack app and all notification moved there and overall I welcomed these changes since the only other way it seems to be email which speaks for itself - limited interactivity and it's becoming less of a notification medium anyway. [1]