Well FSRS is not really working with full reset. It has multiplies associated with a āFailā that is trainable by the user review. Params 11 to 14 here : Anki FSRS Visualizer
The thing with FSRS is that it work really well to learn from your past history. Maybe youāre the kind of guy that need a full reset, or a simple 20% loss of interval will be enough, FSRS can adapt to that.
Still, depending on the FSRS version you can have different behaviour. FSRS-6, which is on beta on Anki beta version right now, work with trainable decay, the exponent of the forgetting curve. This can lead to some Desired Retention (70%) to be lead to very high intervals like multiple years, when the decay is low enough (itās capped to min 0.1 though). FSRS-5 introduced same-day reviews consideration, not that great to predict same-day prediction but quite great to be able to weight differently if one card was failed 3 times in a row the same day instead of just 1.
Switching to FSRS would mean Bunpro would have to either use default params, which are not bad by themselves, or to map the SRS Strictness to map to different Desired Retention (80, 85, 90, 95% could be good values)
Another question is parameters optimization. It is normally done by user but in Anki it requires manual optimization. Automatic Optimization can be implemented but Iād argue having some minimum review number before being able to optimize is probably better to avoid funky situation. Typically, especially in systems were you go from N5 to N1 with what Iāll assume to be harder and harder content, you might get a model that will be trained on N5 content you might already master, and FSRS will become overly optimistic about your parameters, leading you then to have very long intervals for N3-N1 content until you fail them ~6 months later and then suddenly the optimization will change the parameters.
But it doesnāt stop there, another concept of living with FSRS is rescheduling. If you donāt reschedule, the cards planned in 1 year will stay there. So if your params are now less optimistic, youāll have to reschedule cards. But this action is known to lead to immense backlogs since you have maybe 300 reviews to do as a backlog that were initially planned in 6m-12months.
So all in all, I think FSRS is indeed a good way forward BUT itās also paved with gotāchas and not everyone has been very happy with it, often because FSRS doesnāt care about āincreasing retentionā the longer youāve been knowing a word, it just care about keeping your Desired Retention the same, which is why I donāt advice DR lower than 90% such as 80% except if you agree having 1y interval card with a target retention of 80%.
Iāve been using and discussing FSRS for the past 15 months now so feel free to ask.
Iāve listed all the major complaints with FSRS :
Goal here is not to dissuade from it, but more to understand what is the hidden cost that unfortunately many people will try to obfuscate. And also to help Bunproās team to be ready for the potential support required to User, since FSRS will be more difficult to interpret for people less versed in how it is built