Review mistakes after lessons and practices
I think it would be really helpful to be able to see all the questions you answered incorrectly in lessons and practices (including ones that were marked correct but had a 'typo' in them) at the end of each series of exercises. This way, we would know specifically which words we should pay the most attention to and could add them to a flashcard deck or something to reinforce them. It's just not feasible to stop every time during a timed practice when mistranslating a word to write it down and look it up later when the pressure to hurry up is the most pressing exactly when you answer a question incorrectly.
In fact, it might even be easier and more useful to implement the capability to review all questions after a set is done so you can go back and see the explanations for certain ones that you didn't fully understand in their discussion threads. I know that there have been several occasions where I didn't understand why my answer to a question was correct but was too pressed for time to review it and forgot the question by the end of the set.
Yes, this is one of the most helpful features in Anki (the flashcards system). The mistakes you make more often are built into future prompts, so that you are tested more often on problems that challenge you. At the end of a run, you can review your best and worst cards, and track your progress.