We've only been here one day, so we can't make a definitive statement, but it feels like the parks are rather busy--and the counter service establishments are busy--but the table service dining could definitely be worse.
Our theory (based solely on our experience with one friend who had this problem) is that all the first-time visitors taking advantage of the great discounts decided not to or forgot to book dining?
Hmm...
Or else aren't interested in it? Maybe they're trying to save money, so they take the cheap room, but bring a sandwich?
Maybe you were just catching the sit down restaurants at off hours or just slow times?
The last week of January, we had fairly light crowds, but every reservation we had, we listened to multiple people being turned away, being told that they had nothing all day.
Besides seeing that, all of our sit down meals were packed! We did Sci-Fi, Biergarten, Liberty Tree Tavern, Raglan Road (that one was partly empty), 1900 Park Faire (for breakfast) and Le Cellier. Besides Raglan Road, they were super busy! We kept commenting on how people don't understand that you have to plan in advance and make reservations!
I think the restaurants are pretty much always full. It's a just a question of whether it's all ADRs or walk-bys.