It feels like WK somewhat loses its way partway through

It definitely feels like a lot of radicals exist just to gate content. In fact, according to this post something like 323 radicals (or about 2/3 of all radicals) had corresponding kanji on WaniKani. That’s about two full levels worth of redundant items.

While I do like the level-system, I don’t think it justifies that kind of busywork.