Hangout replaces Talk. EPIC Fail doesn't really cut it.
Google Hangouts is primed to replace Talk. I'm not sure if it just replaces talk if you install it or if it's supposed to replace Talk in general. Either way. The App is a fail of epic proportions.
There are basically 2 issues with Hangouts if you come from Talk. The smaller one ( don't laugh until you hear the big one ) is the fact that the online presence status is gone. And with gone I mean gone. There is no green, yellow or red marker left in the entire system. For me this is a major drawback and it suprises me that Google obviously believes this is not important at all. The advantages of having a presence indicator over not having it are rather obvious. For one you can make an assumption on the time frame in which your message may or may not be noticed. Aside from that you know when you're not supposed to bug someone with photos of cats riding a roller coaster while singing YMCA. DnD generally suggests that.
Worse in this context. People who upgrade Talk will not see your NO KITTEN status effectively rendering DnD presence indication useless.
Now what's the big deal with Hangout? The bomb is the contact list. Hangouts' contact list pretty much is a slightly modified version of your contact list ... the entire list. So you have Talk contacts, Google contacts and all the other contacts in one list split into basically two groups. One that wants-to-be-invited and one that is generally considered hangout-compatible and there is no, nada, zap indication whatsoever who belongs where. I assume that this is fine when you have 5 contacts. You can simply make a mental note who can be contacted and who can not. But my phone has slighty more. Actually is has a couple of hundred more. How on Earth am I supposed to tell who of those critters I can and who i can not reach this way? And with reaching I mean reaching and not theoretically reach if he would actually use what he has signed up for knowlingly or unknowlingly.
The presence problem exists elsewhere. ChatOn for example. But at least you know that the contact uses ChatOn at all. Apparently a contact is hangout-compatible if he or she uses GMail for example. It however doesn't tell you that he actually uses it. But it gets worse. There seems to be no way to filter the list in any way. You cannot even eliminate the "phone only" contacts. Naturally you cannot limit it to anything else that remotely makes sense as well.
As a result you can make calls to people who are not online. If this is a Talk contact he will not only miss the call. He will also have no indication whatsoever that you did call. Even better. The ringing sound suggests there's sort of an open line that just isn't answered. This however is a false assumption since it's the same with contacts that are offline.
Oh and there's an icing. You can only make video calls and then fumble to disable the camera. Voice only apparently is too yesterday for such a great app... Specifically great for a mobile phone when you don't always have a sufficiently fast connection for video. Just because you turn video off naturally doesn't mean the other guys do it as well.
How on Earth can one come up with this idea and no one on the team sees the rather obvious problems with it?
The App however has one awesome feature. You can downgrade to Talk. So there's no risk - at this time - with trying it for yourself.
Oh. Did I mention that Hangouts apparently breaks inter-jabber compatibility? Maybe a temporary problem. But something's telling me it probably is not. Which means you would need another Jabber client to manage your formerly perfectly working contacts. Assuming that your Google Account will still work with external contacts in general. Right now it does but if Talk is actually replaced it might not forever.
Hangouts is probably the worst improvement I've ever seen. It's a failure to deliver on an epic scale. It works if you come from Hangouts. But why on earth does it replace Talk? I cannot imagine anyone who actively uses Talk seeing anything in this app other than a horse taking a huge dump right on top of a strawberry cake you're supposed to eat. It completely sucks and you can't even configure the level to which it sucks.