I've lost several hours and some good ideas in the last couple months as I'm re-adjusting to Canvas after a few years in a (hopeless) Moodle: when I draft a rubric, if I don't remember to save it but instead go and change something in the assignment above, I lose everything I've done. But when I try to navigate away from a rubric item and the points don't add up, it stops me with a pop-up asking if I really want to do this.
Surely it is possible to have a pop-up reminding us to save our rubric work if we start to navigate away without having done so!
Please, please, please. Rubrics and the SpeedGrader are one of the best parts of Canvas, but this makes their use significantly weaker.