It is less productive, and whatever slight advantage it may have in some obscure situation is overshadowed by how lousy it is for all other situations. All maximizing does is train people to be comfortable only working with one window at a time, and to experience confusion at multiple windows or any other sort of multi-tasking.
Just look at any average Windows users - they literally maximize everything, simply because that feature is there. I would argue the thought of viewing more than one window at a time never even occurs to the average PC users. They've been trained to think that way by the presence of the maximize button. I've seen plenty of PC users sit down at my Mac and start dragging all the open windows to take up the entire 22" screen. When I ask "why are you doing that stop it" they respond "I don't know." What the heck is that all about?
I don't see how you think its reasonable to change a major function of the Mac OS that has been there forever, forcing all Mac users who expect it to function a certain way to have to adjust to a clearly less efficient system, just because you want to maximize something, which does happen to be how it works in Windows, hence the suggestion to use that operating system.
I am not against some sort of key combination, but it shouldn't be default. You people really need to learn to stop maximizing things.
Also, ignoring all the "fanboys" (who are making a very good argument) by posting rants about how everyone is foaming at the mouth over the mention of Windows doesn't make anyone's point any stronger.
SNAP!
My friend does that. EVERYTHING is maximized, even MSN windows. It makes me cringe when he looks at other windows using the toolbar thingy down the bottom.