Definitely my favourite one so far! Though I will still be experimenting with newer ones when they come out.
A couple features I'd like to see implemented:
Setting a base instance/account and having links open through that instance. I understand this will put increased pressure on the base instance but from a user perspective this is a massive qol update.
Finding a way to upload videos or converting small videos to gifs before uploading without having to go into a third party source or implementing third party connectivity for this purpose. This is probably out of scope for what the app is trying to achieve, but would be a great addition for content creation on Lemmy in general.
The first one already happens, no? Before the last few updates, if you opened a link to a community that "via" another instance, you were kinda screwed. You could see it as a "guest", but not interact to it. In the recent updates, if you try to interact with it, it will open a popup to ask if you wanna open it in one of the instances you have an account.
Dunno if I misunderstood your point, tho.
The second one is kinda hard, because images already put a lot of pressure on instances storage-wise. Videos would be even more, and not only much more storage needed, but also throughput. I don't really see it happening any time soon, not really because of the apps, but because of the platform itself and its federated nature.
For the first point. If I were to click on a link in the comments which points to another instance, I'm basically taken out of my instance and as far as I'm aware, there is no way to comment or like anything in that post within my account. I have hop out of the post, switch to my instance and then go back into the post. It has happened enough times to be annoying for me.
100% agree with the 2nd point. Why I said that it's probably out of scope. Maybe if there was a site like Imgur for Lemmy. But it only makes sense if it were federated which I don't know how that would work.