Yes, it does require leaving a comment. I always give my students a zero grade when I reassign something, so I'm doing all three (posting a grade, leaving a comment, and reassigning). I do get that it comes up in the to-do list, but in accelerated courses that have 4 or 5 assignments per day, the reassignment too easily gets lost in the to-do list. The card-view of the dashboard (or list view) offers the best visualization and UX for students when it comes to reassignments, but I think that same format should be replicated on the grades page (showing the "REDO" label and showing the comment automatically without the student needing to click on the comment button), but more than anything there should be, in both the dashboard and the grades view, a prioritized, highly visible section for reassignments. These are logically the highest priority "to-do" item that a student can encounter.
I've also been having a hard time making screen-cap videos to show my students what it will look like when they get reassigned an assignment because my simulated "Student View" does not let me see the Dashboard from the student's perspective.