Really, all you need to do is press shift + F3 for the node editor and shift + F5 to switch back to the 3d view. I use alternate layouts when I want more changes. I’ll often customize a couple of layouts and switch between the two. I’ve never felt this to be lacking. I wouldn’t gain much from being able to snap the node editor (or any other editor) into the edge of an editor as a collapsible panel.
I do see the value in being able to turn any editor into a collapsible panel. As I said, I wouldn’t hate blender if it were set up that way by default. Its just that, in my opinion, you would only want that arrangement if you wanted to have access to a select set of settings while in fullscreen. The n-panel tries to provide you with this, it just isn’t customizable. We need customization there in the same way we need artist friendly custom pie menus.
I would be ok with killing the n-panel in favor of having collapsible panels If there were a “custom panel” type editor I could use in its place. That would be a lateral move at best and a wasted opportunity to bring out the full potential of the n-panel.
It seems like under the hood its already capable of doing most of what we want. Look at how the blender pro template changed the n-panel. That was done with whatever limits 2.79 template system has atm (It has been said that the interface is built in python). They already plan to add tabs to the n-panel. 2.8 is a good opportunity to make the n-panel a better fleshed out experience.