I've been working on
https://github.com/trane-project/trane for the past year or so, mostly to get around these limitations. I tried to find a way to use Anki or another existing software to aid my music practice, but I couldn't get it to work.
Some ways in which it's different:
- Dependencies are core to the system. For example, if I am learning a music piece, I want to start by learning small sections and only move on to larger sections when I am good enough at the small stuff, eventually ending with a final exercise that tests my performance of the whole piece. A lot of knowledge/skills follow that pattern, but I couldn't find a way to make Anki or SuperMemo understand this.
- It's meant for both memorizing stuff and practicing exercises. I have tested it with your exact example (math problems from textbooks). It works fairly well, but it's at a very early stage (you can look around at https://github.com/trane-project/trane-math, but it still needs a readme). So it's doing the same thing as the students you mentioned. The difference is that the scheduling is done automatically. Review of existing problems and addition of new ones happen without requiring planning or tracking from the student.
- There's an emphasis on generating the flashcards as text files, so they can be shared. I don't understand why people insist of remaking their own flascards every time. If someone wishes to learn guitar, for example, it's my hope they just download some courses and start learning without spending any time redoing flashcards. This design choice probably makes it harder to write the flascards, but it balances out once the flashcards are done and can be passed around.