How reports going to travel agencies suggests that you will not be able to park hop.
Park Hopping Is Suspended
To enter a Disney World theme park, you will need both a reservation and a valid ticket. You should be able to make the reservations using the My Disney Experience app, but we don’t yet have the details on that.
Reports state that you can only reserve one park per day, and that park hopping will be temporarily suspended. This new process will remain in place at least through 2020.
Disney has not directly confirmed this information, but if it has indeed gone out to some Disney travel agents, it seems likely.
We don’t know whether this policy will apply to Annual Passholders.