First walking in WDW is alot. But as mentioned it is doable and broke up in between breaks and waiting in lines. Secondly, stroller or no stroller. I used strollers on 6 trips with my kids aged 1-8 (3 of them, 2 years apart). We used single, double, jogging and umbrella strollers. We drove on all those trips and adding a stroller was not an issue.
Benefits of the strollers. I am fairly strong and always have a hectic agenda so it can be easier to load up the slow movers and go. Secondly we needed a place to put diapers, a cooler with waters, and snacks and sandwiches, jackets and even a small foldable stool for Grandma (she used for the parade). Needless to say I rolled through WDW like a gypsy boss completely aware of the disdain and hatred some others had for my setup and strollers in general.
The stroller is also nice for parade viewing on crowded days. It provides shade but more importantly as the crowds smash in and late arrivals jockey for that one square inch of space in front of your 3 year old, they cannot get in the stroller. So you always have that square footage for your kid(s).
But when my last kid got to age 3 we went with the umbrella stroller. Snacks and refillable water bottles moved to a backpack. I loved the ease and diminutive size but missed a storage area.
Now with a stroller you just don't hop on a ride with the zombie hoard walkers. You gotta park that baby somewhere and hope it's there when you return. Sometimes you enter an attraction a Disney CM takes your stroller to the exit side for you. Sometimes the CM's consolidate the strollers and move them a bit, but you shouldn't have more than a few minutes to find it. But whichever adult gets the stroller they usually do more walking, fetching of the child's chariot, if you will.
Only you know your kids, their capabilities and your tolerance of said attitudes. Their physical size is also an issue, smaller ok...heavier get to walking 'cause pushing them is gonna get old really quickly.
Finally check
https://disneyworld.disney.go.com/faq/parks/rules-updates-parks-resorts/ for stroller size requirements versus your model(s). As crowds increase the rules are tightening.