Oh whatever, I've done desserts at plenty of restaurants throughout college. Another cost cutting idea: appetizers + desserts. You have just as much of a right to be served as anyone else. It's your vacation too, enjoy it. If you feel bad taking up time remember, if you're out of there quickly, there might be someone who didn't know you needed ADR's for a meal and you only having dessert might mean that family gets to eat at a restaurant they walk up to! So see...it goes both ways.
If you like grapefruit, I hear the grapefruit cake at the Brown Derby is awesome.
We really liked the desserts at Grand Floridian Cafe. (Bonus: the place isn't that expensive...comparatively!)
Tutto Italia is great for desserts.
I thought this would be easy to name! Haha...I think I'm usually too full for dessert
Here's some ideas for cost cutting on meals btw: split meals! You can do this at a TS too! So if you want to go into one and split a meal and each get a dessert, they're totally cool with that. I do it a lot at CS places with my Mom. I get kids meals at CS places too when I'm not with her. Many times the adult meals at CS are just too much! Also if you do want to do a TS, consider lunch! There are a lot of resort restaurants that aren't open for lunch, but many park places are. They have nearly the same menus and it's cheaper.
ENJOY!