Ref T4968. If you add a comment to revision you aren't currently subscribed to, the email currently chooses "[Changed Subscribers]" as the action title. This is less interesting than "[Commented]", provided the affected subscriber is you (adding other people is usually interesting).

In this case, reduce the strength of this action below the strength of "comment".

Made several comments in conjunction with implicit and explicit subscriptions. Saw "[Commented]" for stuff affecting me, and "[Changed Subscribers]" for stuff affecting others.