What's hateful is that there's no easy way to override this from
the UI -- sometimes, whatever the script writer's opinion, *I*
want the UI elements, and I want a button somewhere obvious on
such windows that gives me back all of the browser chrome, no
questions asked.
So you want the ability open up a new window without the familiar
interface, that has an intuitive element to return the interface.
I think our ideas of intuitve and obvious diverged somewhere in the
woods. (Although any sort of bone would be better than the current
situation).
The Mac title-bar lozenge actually does this, it allows you to open a
window without a toolbar or other application controls, and to get
them back. Maybe browsers and popups could use something like it?
Not that there aren't reasons to hate it, but it does do what you're
asking for