It's hard for me to say where the exact cut off should be. I'm Ok with resizable windows on my Galaxy Note which is 5.7". Sometimes I make a few windows that are just a little smaller then the acutal screen size and then If they are offset a little I can tap the exposed area of the largely covered window to bring it to the front. At times useful when cutting and pasting for example. Also with HDMI can output to larger screen, which can come in handy. When using easy Debian on my N900 I might open a few windows and then that wonderful stylus helps to get around. But, as I have aged, my eyes are too weak for reading microscopic text anymore...