This one? This is hardly "always". glWUpdateWindowbufferSize was intended to be used only on window resize which is rare event. What do you think happens right now when an opengl gets resized? Exactly the same, the driver reallocates it's buffer because there is nothing better that can be done.The glRenderbufferStorage call you make whenever the user calls glWUpdateWindowbufferSize. That reallocates the buffer that effectively works as the window's back-buffer. This will have to get called after every window resizing.
But anyway bear in mind what i do in this code is wrapping the current driver interface. If a driver implement it directly can do it otherwise.
Also bear in mind that this interface is only some example of what i think would be good. Of course if the ARB would like to standardize a new interface, i very much doubt it will be exactly this one. So dont focus too much on little details but try to see the overall idea.
Anyway i dont need to prove anything to YOU exactly. I dont for a moment doubt that you will dislike anything i propose. Your behavior of a forum troll is well known to me, i dont expect anything constructive from you and i dont care about your opinion at all.