I forget if there's a specific spot for feature requests, so I'll suggest it here.
When a merge is proposed, it sometimes happens that one of the managers might only read the resulting email after someone else has already completed the merge. If one is to click on the merge related links in the email after that merge is complete, the resulting page might be a bit cryptic to some users. The result is the merge input page with the only clue that the merge has already been completed being the small line at the top that sais "Someone-123 is a redirected user, which cannot be merged".
I would suggest a more informative and obvious message, such as "This merge has been completed, click here to see the result".