I do tend to encourage people to go slower, but the main reason why is because I personally know multiple people (on and off of the forum) who started around the same time I did who tried to go full speed, made it roughly 25 levels in, then burned out massively and struggled to get back into studying Japanese. I ultimately ended up overtaking them despite going half their speed. So most of my advice is geared around trying to prevent more cautionary tales like those from happening. Plus, the majority of level 60 posts that I see posted here also tend to be people on the faster end, and many of them neglected other aspects of study in order to speedrun level 60. That isn’t everyone, of course! But I think it is enough people that it is worth cautioning newcomers about.
I think people can make their own decisions about their study habits and pace, but I also think that the vast majority of people who are new to WK don’t fully understand what they’re signing up for when they commit to doing this. I know I certainly didn’t! SRS is something that needs to be learned in itself, and WK’s SRS is particularly punishing in a way that Anki’s isn’t, so it’s quite easy for people to get in over their head, especially if someone starts out trying to balance WK, KaniWani/KameSame, Kitsun/Anki, and Bunpro all at once. With SRS, the beginning is the easy part, because you have less reviews in circulation, and you don’t really have the full picture of what your future workload will look like, until you have a little more experience with it and can see how things add up.
I think the best advice that is most widely applicable to everyone is to choose an SRS pace that you can keep up even on bad days. For some people, this means a lot less work than others! If someone works full time or is a student full time, or is raising children, or has chronic illness or another condition that makes studying difficult, that often means a much lower threshold of daily reviews. If someone is unemployed and fairly healthy, and doesn’t have children, they can probably handle a lot more work without reaching burnout. I think the latter case tends to be more uncommon, though, hence the caution.
WK itself advertises the fast route, despite occasionally advising against going too fast in the level up emails. The program bills itself as a method for teaching 2000+ kanji in just over a year. And while it’s true that you can do this, and some people can handle it just fine, many others can’t. Or at least, they can’t do it while also balancing other aspects of study: additional vocab, grammar, immersion, etc.
I just tend to assume that the majority of people posting on this forum are not able to learn Japanese in ideal circumstances (being able to essentially study the language as a full-time job), and tailor my advice accordingly. Especially if someone is posting about having substantially struggled with learning the language, or had trouble using WK or Anki or whatever. In that case, I think it’s far more useful to encourage people to work within their own limits and reassure them that even failed attempts weren’t entirely wasted. Language learning isn’t an all or nothing situation.
I actually have multiple friends who won’t even set foot in any Japanese language learning community, including this forum, because they’re constantly made to feel like they’re learning wrong for not perfectly optimizing their studying. Both of them have severe chronic illness that makes it difficult for them to do SRS every day because they’ll often lose entire days due to being in too much pain. I also have other friends who have an interest in learning Japanese, but have been unable to commit to even starting because they keep getting told that this or that method is slow or wrong.
I just don’t see how an emphasis on speed above all else is really helpful. For people who want to go fast and who want to keep optimizing their studying, the wider Japanese learning community online already heavily incentivizes and encourages that. WK itself already encourages it. No one is stopping you! But for someone who is struggling, or who is very new to this and maybe not quite ready to commit to a full year of putting all of their free time into this one hobby, a little bit of caution and support can go a long way.
I would never tell someone that they are bad or wrong for going fast, but I do try to encourage a new person to learn how the SRS works, and point them toward information that shows some of the most reliable strategies for successfully using it. I also suggest alternatives to going full-speed, and give some tips I’ve learned myself as well as from others for avoiding burnout. It’s up to the other person to decide if they take the advice or not, but everything that I share is stuff that has worked for me, and which has allowed me to avoid the same pitfalls that have befallen several of my friends.
Plus, every single person I know who is very proficient at Japanese took at least several years to get there. I don’t know a single person who reached a very high level of proficiency in just a year or two. It’s certainly doable for some, if you are sufficiently dedicated and have the free time to pull it off, but for most of us, that just isn’t an option.
I think the best thing is to try to acknowledge that there are multiple options and paths to success, and respect that other people have different priorities, which sometimes includes doing things “inefficiently” for a variety of reasons. But a big part of that is acknowledging slower paces, and sometimes letting people make their own mistakes. You can present advice and recommendations, but it’s up to the other person if they want to take them, and once you’ve said your piece, unless they specifically ask you for help, it’s out of your hands.