What are its greatest strengths and weaknesses? How would you improve it?

There are some more obvious things, like mod tooling, but I'm gonna concentrate on smaller, niche UX issues that I think arise from how it is designed already, because I think there are probably already enough voices who will speak up for the bigger things.

• Inconsistent language UX between lemmy-ui and Jerboa. Specifically, that Jerboa provides no way to specify the language of a post or comment.
• Inconsistent parsing of markdown between lemmy-ui and Jerboa. Specifically. ^Superscript^ and ~subscript~ work fine on single words, but ^multiple words in superscript^ ~or in subscript~ do not display correctly in lemmy-ui. They do in Jerboa.

It's bad enough that third-party apps do these things (and others, like spoiler text) without following the spec consistently. But can they really be blamed when even the two main first-party UIs don't do it right? The post/comment language feature is awesome, as is the fact that you can do such a wide variety of syntax including subscript. But if users are not getting a consistent experience with these across platforms, it leads to confusion.

• Spoiler text syntax is clumsy. I like the idea of having collapsible text, but ::: spoiler [display text] is an insanely wordy way of doing it. In what other context is markdown do anything similar to requiring the literal text spoiler? It would be great if (a) an inline spoiler text syntax could be implemented, similar to >!Reddit's!< or ||Discord's||, and (b) if a more elegant collapsible text syntax could be created.
• Lemmy has a nasty habit of transforming user input. I just found out it converts your backslashes into forward slashes (see this comment), but a while ago I noticed that it completely removes text posted between angle brackets , which is annoying when trying to write pseudo-XML. {does it allow braces?} [square brackets?]. It feels to me like a relatively lazy attempt to sanitise user inputs, and it creates a poor UX, especially since I'm sure prepared statements and other safe data handling is employed. In my opinion any time you're changing what a user wrote, that's an anti-pattern. If you can't just leave it how it is, it's better to just block posting with a clear error message explaining why

Basically, I'd just like to see an overall focus on the user experience and how it all fits together as a system.

Also my little pet feature: keyboard navigation. Back on that other site, before the redesign, there was incredible keyboard navigation thanks to the Enhancement Suite. j/k to navigate up/down through comments. Enter to collapse. a/z to up/downvote. Etc. It's a delight to use, and is a big part of the reason I could never move to the redesign, before I came over here. Not having that is a big drawback IMO.

edit: looks like the angle brackets thing was . Still need the backslash thing fixed.

edit 2: I was just reminded of another example of the lemmy-ui vs Jerboa confusion, as well as another example of well-intentioned by ultimately anti-patternesque transformation of user text: how user and Community mentions are handled.

@nutomic@lemmy.ml will not be a hyperlink for viewers in lemmy-ui, but /u/nutomic@lemmy.ml will be...despite the latter being generally not the preferred way to do it. lemmy-ui also does this awkward thing where if you use the autofill suggestions when typing a name, it wraps them in a hard-instanced URL instead of the better UX of taking someone to their profile on your instance: @dessalines@lemmy.ml.

Communities are even weirder. Allowing the autofill of !announcements@lemmy.ml will create a hard-instanced URL ([!community@domain](https://domain/c/community)), but then the parser ignores this and creates a URL to the user's instance. If, instead, URLs went where the user's text input says they go, but the autofill would default to naked Community mentions such as !announcements@lemmy.ml, this would be a much better experience.

Meanwhile, Jerboa doesn't have an autofill capability for users or Communities. Users who are mentioned with /u/ are not linked, while users who are linked with @ get a link that is handled within the user's instance, regardless of whether it's a hard-instanced link or a naked mention. Communities are also always handled within the user's instance.