So mostly my opinion as members of my family get older is:
Why WOULDN'T you go to wdw? The excellent customer service and relaxing atmosphere can be perfect. The only downside I see is too much walking. Ultimately though I think you can enjoy the parks without seeing everything, so I think the walking thing is kind of a non-starter. If I took a relative who had trouble getting around, I'd just plan a vacation that didn't involve "commando style" running around. We'd just hang out at World Showcase and meander through the parks occasionally. I think it's totally doable even if you have a lot of trouble walking, and without a wheelchair or a motorized vehicle. Am I being naive?