If the choice is between keeping the topic and gmail thinking of the rename as a new thread then I prefer to get the new topic. Maybe for those of us in mailing list mode all you need to do is send another email telling us the topic was renamed. That way when we look at the conversation in gmail the first email is “this a continuation of the conversation in “X Cat Foo Topic” with a new subject line. The topic name was edited at $link_to_thread.” Then no surprises.