Ideally, sure, but in practice the majority will be at the Magic Kingdom every day. People will skip DHS if they can't get a boarding group, and hardly anyone will be headed to EPCOT first thing -- that could change once Ratatouille and Guardians are open, but they'd have to open EPCOT much earlier too (I assume they will once everything is open, but who knows). There's no reason to wait and go to EPCOT at 10:30 if you could go somewhere else hours earlier.
The guests definitely aren't going to be spread out evenly across all 4 parks, and the shorter time period means it may be an overall wash.