Ember has now got one of the best (IMO) release cycles in the business. We borrow heavily from Chrome, and have a very polished release infrastructure, with release, beta and canary channels you can subscribe to. Additionally, we have a strict commitment to SemVer and most Ember apps are on the latest release.

As for the complaint about tying models to routes: Ember does want you to have a model per route, but the model can be any data structure you want: an array, a hash with multiple models, or a single model.

I'm not sure exactly what issue you hit, but most apps of any complexity have multiple models on the page, and of course that's something we support out of the box. (You can see this if you open any production Ember app in the Ember Inspector browser extension, such as http://vine.co or http://twitch.tv.)