The key to selecting the right shoes is to listen to your feet. It doesn't matter what works for others. It only matters what works for your (or your dad's) feet. There is such as variation in each person's size, weight, gait and foot structure that the answer to this question is a highly individualized decision.
Best suggestion is to go to an athletic shoe store in your local mall and try on a large variety of shoes to see which feels better. Be sure to do this later in the day because feet "spread" as you walk around all day. Once you find the pair that feels comfortable as soon as you put them on, you're home free. The only other thing to do is buy two pair and break them both in before you leave for WDW.