As it is, this bag is a good value.  The canvas fabric is acceptably sturdy but it could be heavier; it should stand up to a few years of heavy use, but we'll see.  The main compartment is large enough to take a full bag of groceries or a few large (11x14") sketch books.  The strap cinches up easily so the bag doesn't get in your way when you're riding a bicycle.  One VERY good design feature: the side bottle pockets, which are exactly-sized to take 32oz Nalgene bottles.  They also handle travel mugs well.  Another good feature is the two loops on the outside of the flap, which are ideal for mounting bike lights on.

Downsides are the pathetic interior zippered pocket, which is destined to be chewed to ribbons by pens and any small metal items you put in it.  Similarly, the front pockets don't have snaps or velcro, rendering them unsuitable for loose items.

Given the popularity of this type of bag, the manufacturer should consider a revised or "deluxe" version, with a zippered main compartment; a thicker, possibly removable strap, heavier fabric, a better interior pocket, closeable front pockets, and maybe small pockets on the outside of the bottle compartments.