I really like XMPP, but I’m a little unhappy about the current general situation of XMPP. I think XMPP could do better if there were some benefits of having an XMPP address. For me one of those benefits is to have the option to have just one address I need to communicate to others. If everything is in place and well-configured, a user can be reached by mail, XMPP and SIP (voice/video calls) by just one address.
To address this I would like to see XMPP support in mail clients (MUAs). So when you reply to a mail or write a new one, the client will do a lookup in your addressbook if the address has an XMPP field associated with it and (if not) do a DNS lookup for _xmpp-server._tcp.example.com (or the matching domain part of recipients address). If there is an XMPP address listed in mail header, that JID will be used. When the lookup is successful and an xmpp: protocol handler is configured in the system, the MUA offers an option to begin a chat with the recipient and/or displays the presence status of the recipients (depending on available web-presence or presence subscription).
Basically a good candidate could be Thunderbird, because it already has XMPP support built in, albeit not a good implementation and lacking many modern features like OMEMO. But for basic functions (like presence status and such) it should be sufficient for a start.
Other candidates could be Evolution, Kmail (as KDE MUA and Kaidan as a native KDE XMPP client) or even Apple Mail.app, because Apples addressbook supports XMPP fields for each contact.
Basically the same could be done for SIP contacts: if a SIP SRV record for that domain does exist, the MUA could offer an option to call the recipient.
I would be willing to give some money via Bountysource or similar platforms. Is anyone aware of such a project or willing to write some addons? Maybe within the GSoC?