Lack of granular privacy / profile control

• “The lack of privacy controls … our profiles are public, and all our posts and comments are visible to anyone.” (lemmy.toot.pt)
• Users cannot choose who sees their profile history, comments, or posts.

Poor content discovery / lack of niche communities / limited diversity

• “The platform lacks all the communities … There are no communities for games or music or sports or hobbies or movies or anything.” (Reddit)
• “Not nearly enough people to cover all the niche interest communities that Reddit does.” (szmer.info)

Fragmentation across instances / duplication of communities

• “Multiple communities dedicated to the same thing across multiple instances … causes confusion …” (Popcar’s Blog)
• “There are duplicate communities: every instance seems to have their own version of each community.” (Reddit)

Bad User Experience (UX) / usability issues

• “Lemmy is losing so many potential new users because the UX sucks for the vast majority of people.” (NodeBB Community)
• “Simply using them is confusing … accessing remote subs is a complete train wreck.” (Reddit)

Performance / reliability / scaling problems

• “Slow and unreliable” is listed among cons. (Slant)
• “Servers go down … syncing/federation issues.” (Android Authority)

Moderation, safety tools, and content-quality issues

• “Moderation tooling is not adequate for removing illegal content from servers.” (We Distribute)
• Users report low content quality (memes, shitposts, agenda memes) instead of high-value discussions: > “The politics is always … or it’s toxic American hyper-partisan … The memes aren’t any better.” (Reddit)

Search and archive weak/incomplete

• “Search sucks … Lemmy isn’t.” (szmer.info)
• Lack of long-tail content archive.

Over-representation of particular content types (US-news, memes, agenda posts) and low content-quality

• Users note: heavy US-centric news, lots of meme posts, little local news/events or regional content.
• While I didn’t find direct sources for exactly “too much US news / no local events”, the broader complaint of “lack of niche interest/hobby/sports” covers this. (Reddit)