Ya know, we never hear much complaining from the school about the wheels.

My third grader has one with wheels and loves it

and really truly needed it because of the weight of her bag. My 5th grader does not have wheels because we want her bag to carry over to middle school and they will not allow wheels because of the locker size.
Do you have access to a pottery barn store near you? I absolutely loved the look of those bags, but once I saw them up close they really weren't large enough (or sturdy). IF you are only going to use it for one year then *investment* really isn't an issue but for me, the LL Bean bags were really pricey so I needed to know that they would last a few years.