What if in every world there is a hidden "quill bank" or something that you could find and store all of the quills that you've picked up? If you leave a world or die without depositing your quills in the bank, you have to pick up those quills again when you reenter the world. You can purchase moves from Trowzer with the quills you have on hand, but if you're going for 100%, you have to either deposit the quills you find before each time you leave the world/die, or you have to pick up all 200 quills and then deposit them in one sitting.
Personally, I would enjoy the challenge of picking up all quills in one sitting. But there are twice as many quills as there are notes in BK, so it might be overly frustrating and tedious for some players. For those players... we have the quill bank, which would be a challenge to find on its own!