When I do arc diff for the first time and the editor comes up, it would be cool if the Reviewers field were prepopulated with suggested reviewers or if there were some inline commented-out reviewers. (Or if I could upload the diff without Reviewers, or even just see suggested reviewers in the web UI). I'm imagining that Owners and blame information could suggest Reviewers that are at least good as the ones I select for unfamiliar code, since in practice I tend to just use Owners and blame in selecting reviewers.
Pretty wishlisty but would help make it more lightweight to do small diffs. (Also, blame is absurdly slow in our environment for bad reasons.)