I agree, I feel like the UI could be a tiny bit more clear, and old.reddit does exactly that.
For example, threads seem to lack a tiny bit of indenting, perhaps a tiny splash of bg-color alternating.
Another thing that I have an issue with, is the page auto-refreshing. That's something that really makes me press "ctrl w". I am reading something, it's there, and then it's gone. Nope.
One last thing, and this is particular to the Fediverse - When someone posts a Fediverse link (to lemmy sub on a different instance) and you end up on a the website of that instance, obviously not logged in. You have to copy the link to your instances search... You know what I mean, it just makes it all clunky. It would be nice if Lemmy could check if the link is from the Fediverse, and then offer the option of "opening it locally".
RIF c'est pour Reddit. Je parlais surtout de Mastdon. : ]