As Marc Andreessen said yesterday on Twitter, "Google employees will really enjoy using this"!
I too have little confidence in Google's ability to make a messaging app that people will use.
For such a giant tech company with so many smart people I can't fathom how they've managed to screw up instant messaging so, so badly. They could have easily had the dominance they have with email if they'd just built a nice, simple, cross-platform version of the old Google Talk client.
Instead it mutated awkwardly into Hangouts, something which seems weirdly present in different forms on different devices and embedded into certain of their web applications, with varying levels of functionality.
It bugs me that there's no native Windows desktop client, just some Chrome "app" thing. It really bugs me that the mobile application is is kind of worse than ICQ was back in the 90s - the user list does not distinguish between users that are online, away, or offline. The default view is just a list of your previous conversations. It bugs me that they've hidden the logout option (Settings -> Account settings -> scroll to bottom -> sign out) to basically trick you into running it all the time.
I am very sure all of these 'features' are intentional and the result of UX experts studying how people use the application combined with how their biz people want people to use it. I know their goal was to make Hangouts more like an SMS tool - they want people sending messages regardless of online status. (I've never been a big SMS user so I don't know how important the SMS integration for an Internet-based messaging app is to civilians; maybe it's a bigger deal than I think?)
Before Hangouts almost everyone I know was on Google Talk. My relatives around the world used it as a standard communications tool for quick chats and voice chat. Since it has gone to Hangouts they have all (except for one uncle) abandoned it more or less completely - I never see them online any more and I never get any Hangout requests. They've all moved to Skype for voice chat. No idea what they use for messaging.
I don't want an intelligent assistant. I want to be able to send quick messages to people on my list. I want to know in advance if they're online, away, or offline. I want to be able to set my status to any of those states. I want it to be secure and preferably open source (... realising the latter is a long shot). I want it to NOT CHANGE every few months when some new UI/UX person gets a hold of it. I want it to be simple, stable and reliable.
Please start here Google!