i quite liked element as a replacement for whatsapp and discord when i got a few people to switch. just had too much stability issues at the time and they went back. will never get them to switch again...even with ads and age verification crap going on.

The main complaints about Matrix I've heard though are about behind the scenes stuff rather than features, which the video touches on:

But there are some reasons why I think XMPP is superior. In Matrix, when you join a room, your server downloads and stores the entire history of that room. If someone on a federated server posts illegal content in a room you're in, your server is now hosting it, and you are liable. Whereas in XMPP, messages are relayed in real time. Group chat, MU history stays on your server hosting that room. So your server only stores messages for your users which means that no content caching there is no content caching from other servers. This is a fundamental architectural difference which makes the XMPP protocol better in my opinion.

Personally I don't know that much about it but I briefly looked into what it would take to write a client for Matrix a few years ago and it seemed pretty daunting to work with. Maybe it would be possible to write software that implements more Discord features on top of XMPP to have something that works more smoothly.

Whether or not XMPP is a Signal or a Discord replacement is dependant on the client.

For a Discord replacement, there is the Movim XMPP client, which has group audio/video calls, screensharing (w/audio using chromium based browser), support for gifs and videos within the chat, and very soon Discord-like servers with rooms, after which the dev plans to work on drop-in voice chat rooms.

XMPP is just the protocol, you can create a client which looks like any proprietary alternative like Discord (fluux tries to have the same look for example)

Movim is IMO the best alternative using XMPP and it's adding more and more features the last weeks stay tuned! see here

which features are missing from xmpp that are necessary for most gamer groups? is it the protocol that is missing the support, or specific implementations? genuinely asking since I'd been considering setting up an xmpp server for my gaming groups