In fairness, Wanikani is usually really good at responding to requests, but this is probably on their “this would be good to do” checklist and not their “the site will go down if we don’t fix this ASAP”, “this is having a massive effect on every user’s experience”, or “this has been requested a billion times” checklists.
I definitely agree that I would love to see this implemented because sometimes my mind goes blank when I see a radical, but keep in mind that Wanikani definitely receives a ton of requests on how to improve the experience, and they’re trying to do as much as possible.