Reading criticisms of Lemmy from Reddit and other platforms like HackerNews reminds me of reading criticisms of Reddit from Digg back in 2007-2010, except they're more based on architecture instead of "it looks ugly".
Now there are things that will turn away users. There's obviously a strong leftist culture here, there are less users so less content, and obviously federation is a stumbling block for many people.
But I really think that's ok similar to what people are saying in that Hacker News thread. I wouldn't want all of Reddit to come over, and I think it's better for the culture and growth here to get a self selected trickle/stream of users instead of a deluge.
I don't think Lemmy will necessarily have the same issues as Mastodon because Twitter/Mastodon requires you to know people or know accounts to follow to be useful. Lemmy just requires communities you're interested in and a critical mass of users to drive posting and engagement. We're already seeing greater activity as more users arrive