Personally, I think there will be more room than people think. Just looking at the numbers
Park | Capacity | 30% capacity | # of 4 person groups at 30% Capacity | # of ppl on average day |
Magic Kingdom | 90,000 | 27,000 | 6,750 | 57,000 |
Epcot | 110,000 | 33,000 | 8,250 | 34,000 |
Hollywood Studios | 60,000 | 18,000 | 4,500 | 31,000 |
Animal Kingdom | 60,000 | 18,000 | 4,500 | 38,000 |
So that means there are normally on an average day 160,000 ppl in all the parks combined (mind you those numbers may include people who are park hopping) and with 30% capacity they can have 96,000 people in all the parks combined. That means its only 40% less than on an average day. Mind you, this doesn't account for high volume vs low volume times but still, right now I am guessing even if they opened it up to everyone who wanted to go, you would see a smaller volume than the average. So I think that people with tickets and hotels will probably all get their park options, and most people booking in the next several days will still be able to get into at least one park on most days they are there. Again, I am just looking at numbers and guessing, but hopefully this helps some people out.
I pulled these numbers off the internet in case anyone is curious.