There are two principles that could be used to determine how much you review in a day. I’m talking about flashcards and SRS in general here, not Skritter specifically, although Skritter is obviously included:
- What the algorithm deems necessary to retain the knowledge the student has
- What the student thinks is reasonable based on many and various personal factors (time, motivation, etc.)
I don’t see a way that you could take 2) into account without infringing on 1). If an item is due, it means the algorithm thinks it’s reached a certain threshold and it’s time to review it. If you don’t review it because you don’t have enough time or motivation, that doesn’t have any impact on whether or not you ought to review it, like @apomixis said.
Now, that doesn’t mean that SRS can’t be sane, but artificially lowering the due count to make it feel better is not the way forward, I think. If you haven’t studied for a long time, you will have forgotten many things, and that is reflected in the number of items due. That doesn’t feel good at all, I know, but that’s how memory works.
However, since it isn’t very helpful to give you thousands of reviews in one pile, we have introduced other ways of coping with this, such as a goal mode where you can chip away at the due queue 100 items a day, or however much you think you can cope with. Obviously, the more the better, but that is related to how much time you have, not scheduling of items. This is akin to your hidden queue, with the exception that the queue isn’t really hidden. Think of it like this: We want to show users what they ought to study, without misleading or hiding the fact that they are behind. At the same time, we want to give users the ability to set manageable goals, because trying to clear a huge queue in one day is often impossible and very demotivating. If you think the large number is distracting, try the continuous mode, which doesn’t show you the count at the top.
There are other things you could do, too, and Skritter could be better at suggesting these or helping you manage the problem. For example, you could focus on certain decks first, reviewing the most important things first. You could consider getting rid of decks that you might not really need anymore. If you’ve taken a very long break, nuking your account and starting from scratch might not be such a bad idea. There are even more potential solutions, but some of them would require new features that are tricky to introduce (such as going through all reading prompts and only then going through writing prompts).
To summarise, it seems to me that all these solutions merely make it easier to cope with a situation which only has one solution: catch up by studying and reviewing more (or delete stuff so there’s less to catch up on). Not studying for a long time has real consequences and that’s not something an app can fix. I have myself tackled queues of several thousand individual characters in Skritter more than once, so I know it can be frustrating! But the large number is a reflection of how much I had potentially forgotten. The solution then lies in helping me (and you and other students) cope with that large number, not to artificially decrease it to make people feel better. If anyone has ideas for how Skritter could make coping easier, do let us know!