I have recently replaced my monitor with a 24" wide screen at 1920 x 1080 and I display Word documents at 100% at which the on screen page width is almost identical to the size of the paper it represents (it's actually about 1mm larger).
I can put two complete Word windows side by side in the available screen area, but normally I will display only a single Word window stretched sufficiently to accommodate the extra tools I have on the ribbons. The Word window thus fills about 2 thirds of the
available screen area. In this respect the Word window is pretty much the same width as on my old 4:3 monitor. (With Word 2003, I tend to display a slightly smaller window - and put floating toolbars off the Word area).
At no time does Word display two pages in the window at 100% zoom. However if I view Word at ful screen, it displays 2 pages at 100% zoom. The times when I would need to run Word full screen are so few that it hasn't occurred since I replaced the monitor.
So you do have the option to choose, by simply reducing the width of the Word screen a tad.
Frankly it is the lack of height of the word screen that causes me more problems. The screen is simply not tall enough to display a full page at 100% zoom, but this is an issue I have lived with for years.
Screen height is however a more annoying issue on my laptop :(