The example you give is the kind of thing that Ember is really good at.
You would implement all those interrelationships with computed properties. Each computed property updates automatically if its dependencies change, and each view redraws automatically when the corresponding properties change. All that work of defining events and propagating them through the mediator is stuff that Ember does for you automatically, once you've declared what depends on what.
I'm one of the early adopters who built a rather big application in pre-1.0 Ember. It definitely pays off as the application grows larger.
You would implement all those interrelationships with computed properties. Each computed property updates automatically if its dependencies change, and each view redraws automatically when the corresponding properties change. All that work of defining events and propagating them through the mediator is stuff that Ember does for you automatically, once you've declared what depends on what.
I'm one of the early adopters who built a rather big application in pre-1.0 Ember. It definitely pays off as the application grows larger.