I really like Wanikani, but I think that’s a little disingenuous… RTK 1 teaches 2200 kanji, and when I tried it I could easily add 30 a day. I got to #990, and my reviews never took more than an hour and a half (and then only the day after I skipped a day). My average review time was ~45 minutes per day, getting up to around 50 minutes per day at the end. At that rate RTK 1 would take 73 days. Actually I might go back and finish it off, because now I have Wanikani again I’m finding all the kanji I covered in RTK to be a lot easier than those I didn’t. I think the writing aspect really helps with recognition.
For some more solid data, according to this calculator, your max reps per day is 249. One rep takes about 20 seconds according to my Anki stats, so even at the peak of reviewing this deck will take 83 minutes per day. And that’s to get it done in 75 days. If we allow three months, we can add 25 cards a day, reps peak at 233 which gives us 77 minutes a day.
There’s a lot of merit to both approaches in my opinion, but exaggerating stuff like this might turn people away from an approach that would work well for them so I’d be careful with that. Certainly though, Wanikani demands less time per day since recognition reviews are so much easier than the keyword → kanji production approach.
One note is that adding mnemonics to the kanji actually takes a significant amount of time: doing 30 kanji would take me around 30 minutes, making relatively heavy use of Koohii for inspiration when I got stuck. So that’s on top of the ~77 minutes for reviews we get around 110 minutes a day to complete RTK in 3 months.