Heather,
Thanks for the great question. Apologies for a slow response. Just got back from WDW.
I think what you read makes complete sense. How you tour is often much more important than what day you go to the park. However, both do matter.
When planning a trip to WDW, I try to think about ALL of the following:
1) Time of the year (crowds, costs, weather, and school schedules)
2) Days to visit each park (touringplan.com and tourguidemike.com both provide great advice – although their approaches differ significantly)
3) Touring plans for days we’ll be in the parks. These don’t have to be rigid, but you should have a good idea of what you’d like to do for the first few hours.
4) Time to go to sleep, so we get enough sleep and are able to be at the parks early. Don’t worry - we also plan some sleep-in days. ;-)
Of this list, I am convinced that being at the parks early and having a good plan for at least the first few hours are the most critical to help you avoid long queues and crowds. I recently helped a co-worker plan a trip during Easter week, using this exact process. His family had a great trip (planning to return) and never waited more than 15-20 minutes for any attraction. Never. Easter week. No long waits.
Regarding weekends and crowds, you need to keep in mind that WDW is a vacation destination for most people. Many come for a week (or longer) vacation, and often arrive/leave on Sunday. As a result Sunday can be light, and Monday is often quite busy – especially at the Magic Kingdom, since many families want to go there on their first day. Of course there are many different travel and WDW event anomalies, and resulting crowd patterns are far from identical throughout the year. That’s why I count on other “expert” sources to help me figure out the crowds during my vacation.
Thanks again for the question.