I wonder if anyone has thought of this before, but I’d love to see a chart on the homescreen seeing how my Review Success/Fail rate fluctuates over time.
Whenever I do reviews, I aim to hit at least 80%. Any lower than that, I know I’ve not been studying hard enough, or maybe I need to pull back because I’m busier with life etc.
I wonder if anyone has thought of this before or has built something like this as an add-on? 
WaniKani has something like this with correct reviews for X time period. It tells you if you are studying effectively by using a “learning zone” between 80-90% i believe. When you’re outside this zone it hints that you either are ready to do more lessons if you get the current reviews you have correct too often, or if you need to cut back on new stuff and focus on your old reviews until you are able to get them correct more consistently. This really helps with not overwhelming yourself and reminds you when you should pick up with your lessons again after taking a break. I would love something like this for bunpro aswell, however, currently it only shows all time accuracy and accuracy for the most recent lesson.
I recall a WK scrip that does this as well, from some time in the past.
Using such is what made me realize that, although I like to only do my SRS one time each day, my retention rates are much higher if I do the less than 24 hour reviews for newly learned items.
Curiously, that retention rate stays higher for the life of the item.
So, like, if I review a new word 4 times in the first 1.5 days, versus 4 times in the first 4 days, I will tend to have a higher retention rate for the word studied frequently in the first day or two.