The all-metal Allez frames can take rear racks. If you have this, the best option would be to fit a rack and bolt-on fenders and the widest tyres you can manage (25 or 28mm). This would be quite acceptable for a wet winter commuting bike.
One you know your route, you know where to place your wheels to avoid big potholes. Basically, the smarter you ride the lighter bike you can use.
If you wanted an "ultimate winter commuter" then a disc-braked cyclo-cross style road bike is probably as close as you can get BUT that's just my thinking.

Its always good to think about alternate uses of your commuter bike. If you want to load up and go touring then a touring bike is sensible. If you want to do long, fast endurance day rides, then a road bike is good. For off roading, a front-sus MTB works fine. One bike can cover several bases but over time most of us acquire several, a summer fun racer, a winter workhorse, a fancypants custom tourer. Its always a good idea to have a backup bike for when you have a major breakdown.