We told our 2 year old the same thing. And I figured the slower walking pace would help even out the time it takes to get in and out of the stroller and the fact that I didn’t plan in breaks for diaper changes. We definitely walk faster than most people too.
I’m about to find out for myself when I visit WDW at the end of February with my 13 month old and 2 year old. I anticipated diaper changes, feedings, and (hopefully not) meltdowns so I included rides in my TP that can be skipped giving us a built-in break if needed. I’ve taken them to other theme parks before, and although detailed planning was not required for those parks, they were able to handle it and we were able to stay on schedule.
Lots warned me about too busy of a day, but my 2.5 yo niece had done amusement parks before and was a complete champ. She was awesome for our two days. Just typically crashed in the stroller at dinner. Though she did wake up for a late night ride on the tea cups and buzz.