I get some of what you're saying about lightening the weight of the carrying equipment. But, by definition, with enough stuff to warrant a pannier/backpack/etc. AND any form of normal commuter kit (lights, fenders, etc.) we're already out of the weight weenie zone.

Don't get me wrong, I still drink Diet Coke when I'm having a piece of pepperoni pizza with extra cheese, so I'm all for cutting stuff where you can and every little bit helps. But I'll accept a little weight penalty for sturdy and durable equipment, then trim by eliminating frilly bells and whistles and useless stuff (including some of that extra cheese).