Our first (and only lol) Christmas at Disney was in 2001, nearly 3 months after the 9/11 attacks. There had been rumors of POR (our resort) shutting down due to low occupency, and sure enough, 2 weeks before our departure... we got a call from Disney. The end result though? A beautiful room at the Polynesian overlooking the quiet pool.
My situation is extremely rare, but as you can see, it's happening at the AKL due to their construction. I would never expect to see it happen again unless there are extreme circumstances.
Upgrades are nice, but never expect them. When we stayed at AKL we were upgraded from a standard to pool view, but we were only staying there one night, and had we wanted a certain view room, we would have booked it.
You are always more then welcome to inquire about upgrades... but if you are interested in a specific room type, book it, no questions asked. Christmas is an extremely popular time of year and very little, if any, rooms will be left unoccupied.