Just a reminder that Wanikani is not a vocabulary learning website, it’s a kanji learning website. The vocabulary is mostly there to reinforce readings and the context in which they are used. Of course you can always ask them to add something, but I don’t think there’s a high priority to make a complete and comprehensible vocab list.
If you’re looking for resources that do teach large, useful amounts of vocab, have a look at Torii or Kitsun.