That’s a good idea, and I have an idea for a quick-launch bar for the Open Framework, but it’s not something I’ll have time to implement for a while.
It has never been on the dashboard, but if you have the companion script [Self Study Hide Info] installed, it puts a toolbar in the items-by-level pages (e.g. Vocabulary for Levels 1-10, or “Level 16 items”) that you can launch a quiz from. That makes it super easy to study a level at a time with one click.