I've survived many winter WDW trips. As you note, cold weather and ride closures are not for everyone.
While it sounds simple to say the weather might be chilly, cool weather means a bit more than that. for us, winter trips= packing on the heavy side. Not only do temps drop, but you are outdoors for extended periods of time, and WDW can be quite windy. Conversely, afternoons are sometimes quite warm. For us, that = heavier packing than summer trips. It also means some days we wear shorts during the day, but change into pants around dinner. In terms of planning, that means we usually plan to make a trip back to our room. Some trips, we wear lots of layers and just do laundry.
The WDW pools are heated, and open year round, but well, when it is only 50 degrees, MOST folks don't opt to go swimming. A few die-hards do, and DISers like to brag that they go swimming in all weather, but I've been many times in Feb. MOST folks don't go swimming when temps drop below 70. If the weather is expected to be chilly, BOTH water parks will be closed. At best, often only one is open.
The other big risk we've faced a number of times is getting stuck in FL a few extra days due to big storms. When a large storm sweeps across the lower 48, flights across the lower 48 get delayed/cancelled. You might get stuck in FL for an extra day or two. Also, if you live in a place that sees snow in winter, it pays to prep for the possibility of a storm while you are away. Like maybe hiring someone to plow your driveway while you are away, parking your car in a covered garage, and stocking a few non-perishable canned goods.
Oh, along the same lines, I highly suggest a direct flight if possible.
