I would say it probably depends on what you enjoy in each park, and what your ride and show preferences are. If you don't have any trouble thinking of spending a whole day in one park and another in the other, and plan on booking MaxPasses to stick with each park, then you'll probably be fine. I personally loved being able to book a Guardians FP while in line for Peter Pan and have no trouble going over to ride. But since you'll be there for a few days, if you think you'll get your fill of each attraction you like at each park on the dedicated days you have to them, you'd probably be fine without also.