I recently switched sides from suggesting edits to reviewing suggests. Now I see how when my rejected edits got canned comments (like "too minor...") I didn't really learn how to make better edits.
When on the other hand a reviewer took the time to really explain the reason for the reject I took a step further in understanding what was needed.
The best teachers were those who improved my edit and commented on their edit - for this to generally work we would need the authors of suggested edits to look at their suggests again after reviews happened though.
So for improving quality on AskUbuntu reviewers of suggested edits should take a little more time and tell the editors what in their edit was not appropriate/good enough.