I would maybe stop calling them "vacations." This is more about traveling, going to parks, and actually doing things. A vacation is going to a beach for a week, drinking Margaritas all day, and passing out by the evening. Traveling is where you actually are expecting to be productive and stay busy all week.
Yes, if you expect WDW to be a cruise or a beach resort, you might find it overwhelming and taxing. If you think of it like a road trip or taking a tour through Europe, you might be OK with actually putting some work into planning it.
I think you'll find that if you show up to Europe without a plan, you'll be overwhelmed and end up not actually doing anything.