Personally, I have found WaniKani very helpful. From your description, I believe that it might also be helpful for you. In particular, the whole package of so-called ‘Radicals’ (similar but distinctly different from traditional ‘radicals’) and their pre-made mnemonics (for ‘Radicals’, Kanji, and Vocabs) which all build upon each other. And the graded/gradual levelling system, etc.
In other words, it’s a pre-made system for learning kanji. It helps you build up your knowledge of Kanji and kanji-related elements (aka ‘Radicals’) from the ground up, building on itself. Thus, it’s pretty efficient. Instead of learning a plethora of seemingly unrelated things, you learn the basics first and then use those basics to learn all the related things from there on. Also pretty memorable (compared to trying to learn the same kanji without such break-downs).
Using the system (which can be tweaked easily to adapt your own mnemonics, for example) has also helped me to learn how to learn new kanji, even if they aren’t in WaniKani. Example: recognize known Radicals, build my own mnemonics, learn supporting kanji/radicals if I don’t already know them, use vocab to support the learning of kanji, etc. That’s basically what the WK team has done to develop their system, and there’s nothing stopping one from extending the method to one’s own desired kanji.
That being said (about learning kanji outside WK), WK does already cover:
- All of JLPT N5 through N2 and about 80% of N1.
- All of Joyo (常用漢字) Grades 1 through 6 and 87% of Grade 9.
- All of the top 1000 (based on some frequency usage stats; maybe newspapers?), and cumulatively 81% of the top 2500.
- Scores over 98% on many top lists (NHK Easy, Online news, Twitter, Wikipedia) and just below 94% on Aozora Books list.
So, coverage is very solid from a beginner to intermediate to early-advanced progression. And by that point you will be able to use that foundation to pick up the rest on your own if and when you need them.
Thus, for catching any beginner/intermediate kanji that have currently ‘slipped through the cracks’ in your learning, I’d say it would be an ideal choice.
And, if you already know a bunch of kanji, it’s still not a waste of time to ‘have to’ go through the initial levels, most of which you’ll probably already know. The thing is, if it’s easy, it’s easy, and you just zoom through them. That’s the power of SRS. It’s only the ones you don’t know that you’ll spend any mental effort on.
There have been several posts in the WaniKani community forums over the years of people asking whether they should bother with WK after they already know a bunch of kanji. And there’s almost always responses from people who have started WK from level 1, even though they knew a bunch of kanji, and at the end of the day they don’t regret it – again, largely because: if it’s easy, it’s easy and you just zoom through it.
That’s not to say there aren’t any people who didn’t regret it (or, more accurately, didn’t find WK useful and so didn’t end up using it). There are folks like that also. So, ultimately it’s a judgment call on your part.
And, all of this is assuming that you’re okay paying for it. Sadly, you will have missed the Christmas season holiday discount by just a couple of weeks, so if you’re looking for the cheapest-cheapest deal, you’ll have to wait a year .
But if money’s not a big issue, lifetime subscription is still a good deal (IMHO). Or, if you have a lot of time on your hands, you can do the ‘Speed Run’ paying monthly (or yearly?) and it’s a little bit cheaper. But I wouldn’t recommend that, as it takes a lot of concentrated effort and lots of people end up getting burned out going that route.
Hence, my recommendation is, if you’re serious about learning as much kanji from WK as you can (or want to), using SRS specifically, then the least-stressful, best-deal is the lifetime sub. Even if you already know 600 kanji and familiar with 1000 in total, if you’re serious about learning kanji (via SRS, as opposed to some other way), then it’s worth it (IMHO) to go lifetime. I’m sure there are cases to be made for monthly/yearly, but someone else can help with those cases.
Just my 2¥.