Read and respond to these two papers about progression design in educational games (write just one response). You should notice elements of player modeling as well as automated generation and critique in the design process.
The big A/B test started in the first paper (research conducted in 2013) has been running continuously ever since. You can play the fractions game here (and get randomly permanently assigned to either the original or the machine-generated progression): https://www.newgrounds.com/portal/view/625061
Can't change a rubric once you've started using it.