Samsung and Software ... let's just say that it is not the best association ever.
They wanted to launch a Tizen phone 'Samsung Z' before the end of 2014. Even by their own standards it was not good enough so it has been delayed.
The decreasing sales of the Galaxy line has also prompted a (long overdue) shake up.
I don't know if Tizen will continue to play a role in the upcoming lineup or if Samsung will realize that creating a new mobile OS is not that easy.
They are still pushing Tizen as their smartwatches OS (except for the ones that run Anrdroid). I have been able to test the Galaxy Watch 3 a couple of months before its release and I have to admit that I have been favorably impressed.
It does not transform smartwatches into must-own gadgets (but to be fair, IMO neither do Apple or Google), but it i nice, has cool features (always on hear-monitor) and is almost exempt of the samsung mega feature creep.