This wouldn’t let you continue to review burned items at longer intervals, but somebody previously suggested a ‘demote’ button which would also work to demote burned items back to enlightened (or whatever you wanted), which might at least let you continue to review things over a long timescale. I mostly mention it because Viet commented on the thread to say they would at least consider it:
I sympathise with the sentiment of not wanting to forget things just because they don’t turn up in the reading material you happen to choose, but it really does make more sense to focus on retaining information that actually comes up in the material you consume. I’m sure there will be plenty of new vocabulary to learn, without worrying about retaining obscure words from WK as well!
That said, options are nice. I would just worry that the niceness of WK would leave me forever reviewing words here instead of focusing on learning new stuff…