Due to the reduced capacity limits and popularity, getting reservations to these parks will likely end up being "gamed" in a similar way to Fastpasses. DHS due to its high demand and low supply, is expected to be the hard to get reservation, while with its low demand and high capacity, Epcot is likely to be last to sell out. MK will likely claim the number 2 spot with AK at the number 3 spot though.
As
@MansionButler84 said, there is a large expectation that Epcot will be the available park hop for those that want it later in the evenings.