Since the readings are pretty much always in hiragana, I can read it relatively fast now. But as a result, my katakana has lagged behind, since I have barely gotten any use for it since I first learned it before starting kanji.
So could it be made possible to switch the readings to katakana when learning kanji and vocabulary so I could get bit better at reading katakana while learning kanji and vocabulary?
I don’t think there is a way to do this natively, but there is a script that switches all on’yomi related readings to katakana automatically:
It works really well. And maybe there is another script that will switch all possible usage to Katakana if you look hard enough, but I wouldn’t do that as it might get a little confusing especially for words in Wanikani that use Katakana already.
Even after years of knowing both hiragana and katakana, it’s just natural that I am better at reading hiragana with how much you’re exposed to it. Though what you are asking is a unique way of going about practicing katakana, I would caution against doing it this way. Remember that katakana is mainly used to denote foreign/borrowed words. If you practice katakana by reading things that are normally read in hiragana/kanji, you may end up wiring your brain to not respond to katakana in a good way. Of course this is just my thoughts on the matter… For instance whenever I see katakana I know instantly that I have to think a little differently in terms of reading so I can understand what the word is, even if I am reading it relatively fast and with ease.
For me, the best way to practice both hiragana and katakana is to download a third party app on my phone like “Kanji Teacher” or another flashcard based app that will spit out the characters at you at a fast pace so you don’t have too much time to think. A week or two of dedicated practice like this and you’re golden. I’ve also noticed myself picking up better katakana reading skills the more I am exposed to reading sentences with borrowed words. The “patterns”/“shapes” of the characters next to each other start to become second nature.
頑張てね 
I would suggest against turning all the readings to katakana, since as @GreekCupOTea said it is used for specific purposes - loanwords and often denoting onyomi readings next to kunyomi (but i guess onyomi is sort of like a loanword, a loan reading i guess).
It is hard to get enough practice reading, i have a similar issue, but i found the onyomi script suggested by @wojtaso9 quite helpful since it makes your brain think while doing the readings, and it needs to know how to read katakana to check your answers are right. But while giving you the practice it still keeps the distinction and keeps the katakana within a context you’d usually see it. If you’re looking for more vocabulary with katakana, asides from jsut consuming a bunch of readign material, there are flashcard decks of non-kanji vocabulary on most flashcard platforms.
Hope some of that helps : )
Also, since it’s your first time(s) posting:
\textcolor{MediumPurple}{\huge\textsf{Hi}} {\huge\textsf{@RevDecim}} \textcolor{MediumPurple}{\huge\textsf{and}} {\huge\textsf{@wojtaso9}} \textcolor{MediumPurple}{\huge\textsf{!}}
It’s great to have you here!
If you haven’t already check out the Forum Guidelines and the Wanikani User Guide .
There’s also tonnes of things on the forums to help you on your way such as The guide, The Ultimate resource list, and API and Third Party Apps.
If you have any questions, check out this thread; but if this doesn’t answer your questions, feel free to create a thread like @RevDecim did here, or email The Wanikani staff.
Good luck, and I look forward to seeing you around!
On my phone (iOS) I use the app Tsurukame for WaniKani which is pretty nice. One of the settings it has is to display onyami using katakana. Admittedly though, I much prefer using PC (especially for reviews)
I also prefer using the PC. Much quicker and I am much less prone to making typos on it haha.
Welcome to the community!
Not related to modifying WaniKani, but just as a way to get exposure to katakana, Japanese word puzzles, like crosswords and shiritori, are good places to get accustomed to katakana, because katakana gets used as a convention in those.
I made a video recently where I went through solving a shiritori puzzle.
Just to offer an alternative point of view – though you have a point –, I personally wouldn’t worry about it too much. It’s very common (at least in anime and novels) to replace fairly complex kanji with their readings in katakana, often for the sake of giving them special emphasis, avoiding having to write the kanji, or even just to make it clear that they’re standing in for a kanji and aren’t just some other word in hiragana. (Also, technically speaking, a lot of kanji are loanwords from Chinese, so it’s not exactly against modern conventions to write them with a script for ‘foreign words’. Look at ラーメン!) You might even argue that because this is such a common thing, it’s essential to be able to read katakana with ease, even if you can’t do so as quickly as for hiragana. However, overall, it would still be best to maintain a balance between hiragana and katakana in practice. If you really want practice reading fast, you should try attempting to catch what’s written on screen during a Japanese TV show (like an anime or a game show). The challenge is managing to understand everything before the words on screen vanish!
@wojtaso9 already mentioned it, but this does the same thing for PC (and is probably what inspired that Tsurukame feature): [Userscript] WaniKani Katakana Madness
Personally speaking, this userscript (and some Pokémon games) made katakana much easier for me to read 
Me neither. If you know about when and why katakana gets used, that’s all you really need. The lack of reading practice is more of an issue, also for me I feel. I might actually give a try to the script suggested and see how I feel about it (frustrated likely! 
)
Thank you everybody for the discussion here. I will try using the WaniKani Katakana Madness script for a while because Jisho uses katakana for the onyomi readings and it always throws me a little. Keep having to go back to a chart to read them. There’s like eight of them that are always getting mixed up in my squishy little brain 