I guess I don't get these iMessage issues. If somebody isn't on it, why can't you and everybody else just text them with a normal messaging app that comes with the phone? What am I missing here? Hec I don't hardly even use hangouts because I don't see a big difference.
I think the main issue, which I've run into, is group messaging on android is kind of garbage. I don't know if it's changed on 4.3, but before that it seems to never work, at least it never does for me. I've tried most of the aftermarket messages systems and they are much better, but still kind of crappy.
Also imessage is nice in that it can go to any of your devices, ipad, computer, etc. so you can pickup a conversation wherever you go.
There are probably solutions, but forcing all your friends and family to switch to a specific app isn't a solution IMO. Google needs something that is stock and baked into the OS just like Apple. There also should be some kind of universal standard so different OS can communicate with each other.
I definitely miss imessage, it was very elegant and easy to use with no setup or tweaking required.