Well, no, I meant streamline. Is it called streaming in industry?
Anyway, my point is that, like Dan says, "open" in terms of level design is to do with linearity rather than loading times.
I think some people get confused by Morrowind/Oblivion's style and think that only games which streamline loading can be open-ended. That's far from true.
That's not streamlining, it's streaming.
Streamlining means to reduce something to its minimum components by taking away whatever is deemed superfluous. Streaming means to load the content into memory continuously without stopping the game (or movie, or song, or whatever).
Your point still stands, of course.