The article is a little short on technical details, will only the Gtalk client be retired, or the XMPP interface (ie Adium) too?

So, what impact, if any, does this have on Google Voice, and more specifically, the Asterisk connector (Motif)?

Another sign that Google has lost their way.

It would be nice if they announced end-to-end encryption for Hangouts at the same time. At least then they wouldn't have the excuse of "having to support a legacy system" anymore.