Thursday and Friday (at Hollywood Studios and Epcot) didn't seem too bad (though a bit busier than I'm used to when I travel down here), but yesterday and today (at USF and Animal Kingdom) were busier than I've ever seen the parks before. My group was ultimately able to navigate around fine, and didn't miss anything we wanted to see, but it was striking.
I'm hoping tomorrow (at Islands) and Tuesday (at Magic Kingdom) ease up a bit.