I completely disagree, put on a heavy coat (armor), grab a garbage can lid (shield), and hold a yard/meter stick. I'll bet you fit inside a square yard (even with a backpack, barely fitting is still fitting), your shield is probably on the line (as it should be), and your yard stick is out into the next square (where it will be attacking, otherwise you will be attacking within you own square). Especially if you're using a crazy power that let's you attack all that is surrounding you, it your using a dagger, you'll be running in a circle to get to you enemies (especially if they are in the middle of their 5 foot square).
5 feet is way too big. The square should represent your placement, not your social comfort zone.