re: instantiating controllers - services definitely help, but you still have to design and expose APIs to manage the lifecycle of variables from the controllers, and often times (at least for me), there are a lot of cross-concerns and it becomes impractical to have services to deal with each permutation of concern groups (this is especially a problem in more exploratory projects). I should note that in the cases where maintainability suffers the most, I have upwards of 5 core model entities and a dozen other auxiliary ones being manipulated in a single page.
Also, when things need to persist across route changes, then you're pretty much stuck to polluting $rootScope (or worse, $cookie)
re: "Bi-directional data binding should never get you into a loop if you take care to only use the APIs in ngModelController"
Yes, they shouldn't, but under some unexplainable circumstances they do, even when I'm explicitly avoiding all the other undocumented traps (e.g. isolated scope interop, etc). One very big weakness in Angular is internal integration testing. Given enough moving parts, even simple things that should just work start breaking in very strange ways (looking at you, ng-if).
re: instantiating controllers - services definitely help, but you still have to design and expose APIs to manage the lifecycle of variables from the controllers, and often times (at least for me), there are a lot of cross-concerns and it becomes impractical to have services to deal with each permutation of concern groups (this is especially a problem in more exploratory projects). I should note that in the cases where maintainability suffers the most, I have upwards of 5 core model entities and a dozen other auxiliary ones being manipulated in a single page.
Also, when things need to persist across route changes, then you're pretty much stuck to polluting $rootScope (or worse, $cookie)
re: "Bi-directional data binding should never get you into a loop if you take care to only use the APIs in ngModelController"
Yes, they shouldn't, but under some unexplainable circumstances they do, even when I'm explicitly avoiding all the other undocumented traps (e.g. isolated scope interop, etc). One very big weakness in Angular is internal integration testing. Given enough moving parts, even simple things that should just work start breaking in very strange ways (looking at you, ng-if).