That would be awesome, but I don't have high hopes - Google probably wants to have ability to modify protocol as they wish for new features. It seems they practically have no will to build a translation layer :/
That doesn't make a lot of sense though. There are already lots of places where that stuff is falling back to "Sorry, can't do this".
Ignoring hardware limitations (running hangout on a phone without a front facing camera maybe?) you already have the 'user runs a browser that needs a plugin to fullfil the request, but plugin is missing' case. Which is reported as a failure to both users (with a somewhat helpful message).
Using anything hangout-y over xmpp can fail for all I care. That's not the problem. The problem is that they broke the parts that _map well_. You cannot text me if you're using hangout (unless you're on gmail.com and use the 'gtalk' chat widget). I cannot see your presence.
There's a difference between 'not building a translation layer' (for oh-so-awesome new features) and deliberately breaking things that work since, like, forever.
I agree with the sibling: It's deliberate and just another Google 'Move to out platform and never get out' move.
(Other examples: »"Upgrade" your browser to Chrome.« »Install a "modern" browser to get automatic translation of websites.« - ignoring all the 'Join G+' nonsense)
