Increase the difficulty to master words
The difficulty to master new words needs to be re-adjusted back to the old formula. Currently, it is too easy to "master" them. I've already mastered a few words that haven't even been incorporated in some of the exercises.
As I understood the new method is some sort of adaptive spaced repetition. So you may see them mastered now, but in some time (depending on the algorithms and your level) the mastered will disappear and you'll have to repeat them again. Which is more effective than "learn and master it once and for all".