I think we are looking at this the wrong way. There won't be a vaccine any time soon, no amount of testing to guests can be done reliably (and it probably legally not even allowed (privacy). You can't mandate masks, that just won't work.
Disney can really only control things from their side -- limiting capacity, employees wearing masks, spreading out queues (somehow), etc. Thus the purpose of this thread to discuss "reduced or modified experiences" ..
And then just let people decide for themselves to take the risk to go. Disney needs to worry about making guests feel safe and protecting the employees. If an employee doesn't want to risk working there, get them a job temporarily that doesn't put them in close contact with guests.
If employees get it, give them "free" sick days and have them self-isolate.
Though .. the problem is probably less about the virus going forward but about the economic disaster that will befall us because of it and a huge percentage of the population will no longer be able to afford Disney. Our culture will also shift as our priorities change because of the lockdowns.
We'll have modified experiences simply due to severely reduced demand in the tourist industry.