I'd like to see some sort of continuous practice mode that ends only when you decide to end it. In this mode you wouldn't have hearts, but the questions you receive will still be based on your past performance (i.e. Shows more of what you are weak in and less in what you are strong in). Perhaps we could even have a check list where we can customize the content we want. Like if I want to practice content from the lessons Animals, Food, and Adjectives I would choose all those and start the practice.
Another good thing to add would be a review at the end of the session. So, it shows you what you missed and why, words strengthened (at least some of them, like they do now when you finish a lesson), skill points earned, and possibly, number and/or percent correct/incorrect. What do you think of this idea?
I want this also. I like the simplicity of not having to decide which portion you're going to work on next. I'd like to not have to deal with the tree at all and only decide on when I want to start and stop with intermittent feedback and stats to demonstrate progress. I'd also like more specific achievements instead of arbitrary ones like coins and crowns and whatever. I'd prefer to be told my level of mastery for vocab categories ("you've mastered 22 prepositions!") or verb conjugation. These could be options as well--things to choose to strive for--but my personal preference would be to allow the algorithm to decide what is most useful to practice at any given time.
I thought you were asking for timed practice an unlimited amount of questions, that's what I'd prefer provided that between hitting "Check" and "Continue" the timer paused so that you could take a short break. I like the idea of constant questions with no pressure to get them right though and I'd like it if in this form of practice if you get an answer wrong that same question and similar questions came up later during the continuous session.