As we come to redesigning the add word frequency option, we're thinking that it's not very easy to understand. Even if you get that it controls how early in your review session the kitten starts adding new words, you still don't know how early each option corresponds to until you've tried them, which takes a while.
One option we were considering includes a slider paired to a review bar, such that you could choose how many prompts remaining you'd have before you'd start seeing new things. You'd also be able to slide it all the way to 0, or choose "manual" such that it wouldn't add anything unless you told it to.
But even clearer would to just have two settings: "automatic" and "manual". "Manual" would be the equivalent of pausing all your lists, and "automatic" would be our current default add word frequency. This option would be on the practice page next to the active lists display, so it'd be easy to change.
You also will now have the "add word" button sitting next to the "added" bar, so it's easy to manually add a word whenever you like. It seems to us that that's a more straightforward and flexible way to control new item flow than a choice of different automatic addition speeds.
We checked the data, and 191 of you have changed your add word frequency. We can't easily tell how important it is to those of you who did, though, or how much you would want that setting if you add a "manual" ("pause all lists") toggle and a manual add button.
So that's our best idea. Please let us know if that wouldn't work for you, if you love the add word frequency control, if you had no idea what it was anyway, or if you have a special use case to be considered.
Thanks!