I think once the dust settled in like a week or so, you can pick out which scripts are definitely not being updated and you need for WaniKani, and make a request for somebody to create a new version of them in this thread: What do you want now? (Request extensions here)
I mean, you could request them now but it’s unlikely a script author has time to work on new scripts at this time. You can also just drop a comment in the original thread of the defunct script; maybe the script author or someone else will respond and update it.
I know it can be annoying but consider this: in a week or so it will all be back to normal, and what is one week compared to the rest of the time you used WaniKani. For me personally, this update is just a reminder that the WK staff still cares about WaniKani and updates it, they could just leave it like it is and not care for their community at all. But I’m glad they don’t!