This would be a feature suggestion, especially where you have responsive articles in collections that span across Phone and Tablet top level nav.
ie: same collection has two layouts applied - one for tablet, one for phone.
Dream scenario would be a layout for iOS phones, tablets, Android phones, tablets.
Not too much of an ask, is it?
I had posted this same request a few days ago. Neil indicated that it's a feature they intend to deploy Q1 2016!
This would be really good. Hope this will find its way to the right desk.