No I don't miss the zipper. A big button or such and the loop is all that is necessary. SOme are using the magnetic snaps. Since everything has a place inside with all the pockets, it did not matter to me there was no zipper.
There are only two sizes: large and small. Small is pretty small. Too small for me and the average women I think and I don't carry as much as most in my bag. As far as fabric choices, that is what is nice-you can personalize. Just make 'em mom and stop worrying. YOu know what your girls like, so make accordingly.