I've always worn a comfortable pair of sandals when I go, but my skin is easily irritated, and the plastic thonged or even foam thonged sandals tear my feet up! I bought a dressy looking pair of heeled silk thonged asian-flair sandals and fell in love! the bottom is foam support to give a bit, and the silk is easy on my feet...the concern about getting on/off rides isn't so bad. I take my shoes off and stow them for rides like Soarin' but I've also worn them suspended in the air on the Dueling Dragons Coaster multiple times with no problems. I will say if you're prone to tripping and falling, it may not be easy to keep sandals on even walking...this next trip in October will be my first with the Crocs' Sassari style sandal, and I'm excited!
Oh, one more thing I find that helps me deal with the inevitable pain of park-hopping and playing till you drop is to take a single asprin at lunch time, when your feet are still pain-free but about to hit the "I need to sit down!!" point. I find it so very hard to enjoy the Disney magic when my feet are aching!