Issues that would be solved by time/gaining more users

• Not nearly enough people to cover all the niche interest communities that Reddit does. At Reddit you find an expert on almost any topic to help you with your problems and you'll find information on pretty much anything. Lemmy isn't there yet.
• Not nearly enough history. A lot of content is still good and informative after many years. Lemmy doesn't have a library of old-but-still-relevant content to search.

Issues independent of user count

• Search sucks. Reddit's search does too, but reddit is easily searchable via Google. Lemmy isn't.
• Onboarding is difficult, because you have to choose an instance, which is hugely important, but a newcomer has no idea what makes/is a good community to join

Issues that get worse with more users (aka, the potentially deal-breaking issues)

• Lemmy scales terribly. Every larger instance needs to retain a copy of pretty much all other content out there, and each comment/like/delete/update/... needs to be propagated to every other major instance out there. Adding more instances thus increases complexity and cost instead of decreasing it. Running a major lemmy instance is already prohibitively expensive now, with just about 50k monthly active users. If Lemmy was to scale to Reddit numbers (1.1 billion monthly active users, roughly 22 000x the number of users), everything would just break down.
• Moderation work scales just as terribly. Not only does an admin need to make sure the communities on their instance are moderated, but they also need to moderate all other communities on all other instances.
• Related to the last point, there's some legal issues as well if an admin doesn't moderate all other instances. Since content is copied from other instances to your instance, illegal content (e.g. illegal pornography, copyrighted works, ...) are also copied to your own server without your active participation. That makes it legally mandatory to moderate all other communities.
• Legal pitfalls in general. If lemmy becomes sizeable enough, all sorts of laws in regards to social media platforms will apply. That's one thing if the social media platform is run by a huge corporation with a legal department, but it's an entirely different story for a tiny group of non-profit idealists running the social media platform.

Same as with every other social media ... the people.

It's complicated. I've been here about a year and I'm still not sure how to use it properly.

lemmy.ml and its admins being the developers at the same time.

Lemmy was architected by people whose philosophical intentions are out of alignment with the software they cloned.

That system was designed to invite as many idiots as possible, to bait as much engagement as possible, with virtually no controls on quality or intelligence.

Well congratulations Lemmy, you've made the next Reddit. There's no reason to be here, it's just a pile of morons for the most part.

1. Not enough people.

2. People here are way bigger smug assholes than even Reddit.

3. Sense of invulnerability and mod neglegence just because Lemmy is defederated. People naively think that makes it invulnerable to similar issues as Reddit (like toxicity/hivemind/bad modding.)

Back in 2023 I joined Lemmy because Reddit got rid of 3rd party apps. At first I was extremely impressed with the content here. While the community was small, meme channels were hilarious and had fantastic content. Same with the nsfw communities. However, now all the communities are filled with AI slop, political ragebait posting, onlyfans subsciption bait posts, and various other trash. So as far as I'm concerned Lemmy seems to be circling the drain. I can't in good faith tell anyone I know to switch to Lemmy. If a friend were to ask me "hey man, how's Lemmy?" My honest answer would be that it kinda fucking sucks.

The lemmy.ml instance not being treated the same as the rest of the Triad in regards to defederation

Some highlights from the link:

"Don't worry guys, the Uyghur Genocide was REALLY just birth control! ~dessalines, .ml admin, dev https://lemmy.world/post/30580167

"See! nobody died IN Tiananmen Square, just AROUND it, so it doesn't count!!" ~ Davel, .ml admin https://lemmy.world/post/30673342

.ml admin, Nutomics continued transphobia https://lemmy.world/post/29222558

CW: Original transphobic Comment from Nutomic

"NK is actually good and anything counter to that is Western propaganda!" ~dessalines, .ml admin, dev https://lemmy.world/post/31595035

General negative sentiment to other instances who haven't "seen the way" yet ~davel, .ml admin https://lemmy.world/post/27426510

"If you don't support Russia then you just don't understand geopolitics" ~dessalines, .ml admin, dev https://lemmy.world/post/27352415

And a long list of bans/censorship and allowing the proliferation of known propaganda and misinformation outlets clearly demonstrating use of their instance and recognition to force a political narrative

Niche communities. Large spaces are built of small niche interest groups. The tooling around small spaces needs to be first class if we want the larger space to be healthy