It will come, I wouldn't hold your breath on the 'timeline' they posted online. Projects always have delays and I'm surprised they even posted a timeline.
The idea for Wifi Calling on iPhone's thread Telus say in it they were working to have it live in 2015, but it took until 2017 to bring it out.
I'm guessing since they have the backbone, bringing it to Android won't take years, but I wouldn't be surprised if it wasn't until the Fall/Winter or early next year.
I find it a little strange as well considering WiFi calling was introduced by android a couple years before apple introduced it. All of the major carriers in the US have it available for android as well. Not sure what the holdup is as the infrastructure is already in place.