I've finished adding all the RTK1 cards 2-3 months ago and I've now started a new deck with vocabulary. Whenever I go back to reviewing the RTK deck, I tend to mix up similar ones more than I used to do before. It's not super time consuming, as there are few reviews, but I'm sometimes wondering whether this is useful at this point.
Would you guys advise eventually stopping RTK? I feel like it's pointless to keep remembering fine distinctions (i.e.: exact keyword) when I see stuff like "kitchen" being written with "pedestal" + "place".
You shouldn't stop RTK reviews, because you (probably) won't get the writing practice elsewhere (and it's this practice that ensures the best memorization), but you must definitely find a way to differenciate the keywords so you can differenciate the kanji in your mind: some people tweak the keyword, some people add a reading, some people put an exemple word. Some people switch to the Japanese keywords deck.
I can only speak for myself, ten years at least? I have so many leeches, but they're slowly decreasing (extremely slowly). My RevTK deck is already half-J tweaked, so I don't see why I should stop: there are so few reviews when your deck is really spaced...
As per Nukemarine's and others suggestions, I have been writing down the word when performing vocabulary reviews. I'm closing in on finishing Core 2000 and by my calculations, the vocabulary covers more than 1/3 of the kanji in RTK1. I'm figuring that by the time I finish Core 6000, there will be decent total coverage. I think I will be able to lay off the RTK reviews at some point. I find it more useful to remember the kanji in terms of vocabulary anyway.
Speaking from my own experience, I think it depends on whether you want to be able to write by hand (from memory) or not. If you don't care about that, then yes, it becomes redundant. If you do, then by all means, keep reviewing.
I haven't been doing any significant writing practice for maybe, six months or so? but I have no real problems with stroke order, etc. I can write most stuff if it's in front of me, or if I know it by heart. Of course, the whole recall thing deteriorates without practice. I've started doing some kana -> kanji production recently to help that out, after giving up on JRTK.
As for the whole 'best memorization' thing, I think it's really a tradeoff. With vocab, you need to consider whether the additional time spent on writing it down is worth the potential benefit. Given that the extra time really adds up, I personally didn't and wouldn't do it for vocab reviews, since I think volume is more important.
I find exposure i.e. reading works better for truly cementing words anyway, so I'd rather learn a lot of words up front and spend more time there. However, I've found typing (matching input to kana) to be quite helpful, while not taking nearly as much time. I consider it a happy medium.
I made the mistake of switching to recognition reviews (kanji on question side) then stopped reviewing altogether. There's benefits to keep reviewing. The big one is kanji that are not making everyday appearances are still being seen in your reviews.
Mind you, I'm not the type to write down every word I don't know when I come across it. I leaned heavily on RTK for times I'm just watching TV and the kanji's meaning helped fill the gaps of what I'm seeing in the subtitles. When I stopped reviewing, over time I noticed the gaps were not being filled in because I could not quite place the kanji even though I had studied it.
That same could be said of vocabulary, but I have my doubts. A majority of us are likely not going to learn 2 or 3 words for every Kanji in RTK1 (or 3). Kanji are just this quirk of Japanese and Chinese literacy that allows us to comprehend meaning (and hopefully a rough pronunciation) on first site. With vocabulary in all languages, there's that baseline you need to achieve, then get on with exposure and use.
Anyway, I caution against stopping reviews or turning them into recognition type reviews. If one needs to speed up reviews, don't physically write them down which should save lots of time. The same suggestion works with vocabulary when you get to the point where physically writing down the word feels redundant.