(warning, heavily opinionated post follows)
I know it's asking for a lot, but it would be really cool if Pidgin
would have 1st-class out-of-the-box support for Matrix.
I don't want to get into discussions if it's better than Jabber, because
I don't really think it is, but since the momentum is on Matrix rather
than XMPP, then I'd say that Pidgin could use the fact that currently
Matrix lacks a proper client. By "proper client" I mean something that
is feature-complete by standards of year 2000 (actually good software,
like Pidgin), not 2020 (which features broken, half-ass web prototypes
that people call software).
It would probably help with fighting the parasites like Discord, which
is way too popular than it should be.