An underrated feature of Lemmy that I appreciate: Default ranking for comments balances new comments and comments with many upvotes
On a large subreddit with more than 100K users, it's an unspoken rule that if a thread has more than 200 comments, don't bother making a new comment because it will get buried by the default comment ranking and no one will interact with it. Nobody uses the "new" ranking because you're only going to see the meaningless one-sentence comments from people who don't care about visibility. Only reply to the top comments in the thread after that point if you want to have a discussion.
I really appreciate that Lemmy's default comment ranking lets the most upvoted comments fall off the top of the thread after a while so that newer comments appear at the top instead. It prevents threads from looking like circlejerks where all of the top comments agree with each other and encourages people to add their thoughts in a new comment instead of dogpiling on the top comment. This combined with disabling the global karma count is what improves the discussion experience from Reddit most, in my opinion.