If it were my commute, I'd add the rack & put the backpack on your Allez. Then I'd look into getting wider tires & fenders. Full Fenders are great & I'd recomment those if they'll fit on your bike, but even those little clip on ones will make a difference. Wider tires will give you a more comfortable ride. (Also lower Tire pressure will be more comfortable as well. If you are currently inflating your tires to the max PSI, try lowering that a bit to smooth out the ride.) The fneders & rack can move over to a new bike if you do pick up a commuter in the future. As far as the puddles go, I haven't ever really heard of anyone carrying a bike over them. As you get to know your commuting route, you may find some puddles that hide large potholes in the pavement. Those you may want to ride around, but other than that, the fenders should keep the spray down from the rest of them.