Thanks all!
Seems like only issues will be straddling rides. I can tuck my dresses between my thighs on rides like test track, etc. And they aren't short, just a bit above knee (I think 3 inches I said earlier is shorter than they actually are). I said fit/flare, but that may not be accurate description.
I won't wear a dress on Animal Kingdom day - Kali River Rapids, I don't want to walk around in a wet dress.
My thighs don't rub luckily! I walk 7-9 miles a day (work, walking home from train, etc.) and never experience it, even when it's hot.
Obviously if it's a stormy/windy day, I'll wear shorts. Just nice to have the option of a dress if I want.

Especially for days when it will be more meandering than going on rides.