I assume MK is still the busiest park on Sat because that's when most people arrive, but with the lack of fireworks, parades and magic hours does it matter which park you go to on a given day? We are arriving the second week of June. Thanks
If your MK question is "On which day of the week is MK the most crowded?", then Saturday is still the answer.
If your MK question is "On Saturdays, which of the 4 parks is the busiest?," then DHS probably has the longest wait times.
As far as overall strategy, the advice that makes the most sense to me is to do DHS on a weekend, since it will be busy every day and you might as well do it when the other parks are busy. It does appear that MK is a bit less busy on Wednesdays and Thursdays. But it probably doesn't matter too much, and things are always changing.