The removable back-pack straps are a nice feature, but for this size bag, it seems very unlikely to ever be utilized, esp. if the bag is packed completely full.  It would probably be more practical to lose this feature & have the back pouch/panel be more packable/utilitarian w/a lockable, zippered pouch (sans back-pack harness attachment assembly).  Perhaps 4, omni-directional wheels instead of 2, uni-directional wheels might have been nice, although from a form/function stand-point maybe not as practical or as stream-lined.  Also, although it could be secured w/a cable lock b/c of the ribbon-loops on either end of the front accessory pouch, it could have used w/an actual lockable zipper.