This has definitely changed. In the pre-1.0 phase, Ember was supposed to move quickly, to iterate and figure out what the right abstractions were. Since the pre.4 release and the PeepCode (https://peepcode.com/products/emberjs), the core team has committed to keeping the APIs stable.

From this point forward, master is committed to having all the examples in the PeepCode working until 1.0. It's been a long and wild ride mck, but the turbulence has stepped down a notch for sure.