But fortunately I'm not starting out from scratch. People have made those experiments already. Grades suck.
Among other things that do work, guided retrospectives are one idea I would be tempted to implement. (Hell, we software developers know that too: when we want to get better, we hold retrospectives, we don't ask the scrum master to assign a letter grade!)
A small amount of urgency can be helpful, but ideally it should be intrinsic (i.e. someone screaming at you or giving you letter grades is nowhere near as motivating as feeling that you can almost do it) and it's very easy to overshoot.
Good scholastic performance by students in East Asian is not because schools in East Asian countries are low-pressure academic environments.