From my experience translating light novels, I would say reading Japanese is (by content) a 30-30-40% split between Kanji, Grammar, and Vocabulary. That means that no grammar or vocabulary (outside of WK, I mean) would equal an estimated 21% literacy ability. Even then, those numbers do not reflect the time required in order to navigate weakness in those areas, where I’d change them to likely 10-60-30% (Kanji, Grammar, Vocabulary) for time required to acquire understanding.
Knowing Kanji means you have to look up less kanji and have a higher chance of at least a vague understanding of vocabulary, but looking up kanji is simple by keeping a tab of Jisho open and searching by radical. In addition, kanji are likely to repeat themselves, so taking new kanji to memory means you’ll rapidly speed up.
Grammar is the hardest of the three to simply look up, as even having a basic understanding of how a construction works doesn’t guarantee you’ll understand how it functions every time it appears. Grammar, however, in Japanese, is quite consistent to my experience, and, if you can read every word in a sentence, context can often guide to the proper meaning.
Vocabulary is the biggest monster for reading. While you can look up words just like you can kanji, it’s likely you’ll have to look up more words than you will kanji, as you are in no way guaranteed to know what a word means even if you know all of its kanji.
All that being said, don’t give up attempting to read native Japanese! Wikipedia is not the best place to start for exposure to good Japanese necessarily (just as English Wikipedia is not always the best source for English reading!), but the ability to set the English and Japanese pages side by side will help you understand grammar and context of words that otherwise may seem identical to other synonymous terms by translation.
As @xyzbuster said, you will inevitably have to face the raw material at some point, so testing the waters now is not a wrong move. 
Just never let yourself get down over the difficulty, and pace how long you spend doing it. It’s a great experience to witness first-hand how much each level of WaniKani allows you to “peek” into Japanese whether you know the grammar or not!
WaniKani has done much for me personal in my ability to understand written Japanese due to my prior experience before starting, but it has made me able to actually read it (as in, pronounce what I read as Japanese as opposed to just turning it into English) significantly better. While I used to only be able to translate the text of Japanese games I play, I’m now pretty good at reading the lines with the voice actors (as I’m greatly enjoying doing with the new re-release of Utawarerumono on PS4).
