To add to the other replies, try the Lemmyverse search engine, too.
Coelacanth
Lemmyverse is a search engine for Lemmy (though it doesn't find communities on Kbin (yet). It can help you find communities you're looking for, and also shows how big they are so you know where to go for most activity.
Sub.Rehab and RedditMigration.com are indexes of communities that have at least created a counterpart somewhere other than Reddit (though they don't track activity so some might be rather small still).
I have no doubt in my mind this will be an amazing RPG, I just hope it will also be a great Baldurs Gate. I have so many memories of those games, and they have such a legacy that I hope this will be an actual sequel with a real connection and real returning characters (playable or at least prominent, not just mentions and references). No matter how great it plays, I will still be disappointed if this ends up being Divinity: Dungeons and Dragons.
Kbin doesn't have an API and so it's probably less straightforward to dev for. Plus Lemmy is older and more established. I believe ljdawson said in a comment somewhere that he'll work on Kbin integration somewhere down the line. I think that's the way it will go for most of the apps.
Yeah, keeping the content flowing will be the most important thing, and it's much less daunting than taking on moderator duties. Everyone on Kbin/Lemmy right now is basically an early adopter, so they might need to take more responsibility to keep momentum up. It's too much to ask people who usually just read news on their niche subreddits to suddenly start up their own community here, but everyone can take one step "up the ladder" so to speak, and we're already seeing this to some extent I think. Lurkers trying their best to be commenters, commenters putting up their own posts and regular posters starting their own communities.
A lot of UX work still needs to be done for sure. Not sure if it's exactly what you're looking for, but there are scripts to redirect links to your home instance if that's what you mean. Try these (requires a userscript extension like Violentmonkey):
Yes, 60 is pretty much a goldilocks number that is small enough to be easily graspable for most humans, but still a highly composite number (11 factors!) so it is neatly divisible into many smaller units.
While I agree with everything you said, it did also serve a tangible purpose on some subreddits as a barrier-of-entry to prevent bots from posting OF spam or whatever or stop new troll accounts from being able to post.
Makes just about as much sense as communities being called "Magazines" and threads being called "Articles". There is a lot to like about Kbin but also a lot that boggles my mind.
I'm sure most Lemmy apps will add Kbin support down the line, too. The lead developer for Sync for Lemmy already said he's looking into it, I believe. At the moment, Kbin doesn't have an API though, so it's less straightforward to approach I guess.
For an app designed for Kbin first and Lemmy second, Artemis is under way and you can follow it here: https://kbin.social/m/ArtemisApp
I do like a lot of things about Kbin, and visually it's much better than unmodified Lemmy in a browser, but it also has its own share of problems, not least with intuitiveness. I don't understand why communities are called Magazines, and the terminology of "Favorite", "Reduce" and "Boost" are very confusing to me. Trying to make a new thread might lead you down a microblogging path instead since "Post" sounds more like a new thread than "Article" to a newcomer.
There also seems to be much slower sync between Kbin and various Lemmy instances compared to intra-sync between lemmy instances themselves. Kbin also doesn't have an API (yet?), but a more tech savvy individual than me will have to say how big of a deal that is.
Both Sync and Boost have large and loyal userbases and will probably attract plenty of users to Lemmy, and good Third Party Apps might help with first impressions and onboarding for new users.
Ultimately though, content is king. I liked Kbin better when I first made my accounts, but then we had a Race Week in Formula 1 and the community here was dead while discussions were happening on Lemmy, and since the sync was slow so I ended up over there.
While this is always part of it, I've replayed them a couple of years ago and they still hold up. So much of their charm hasn't aged at all: writing, characters, story and voice acting. Irenicus is just as sick of a villain as he was 23 years ago.