This is exactly why I see them adding it to Genie+. Would love it to be free tho, I don't think they will because that would require an extra system to keep those and how does that work for ppl with Genie+? Does it count or not for their time windows? If it's free, I can see it running out a minute after park opens since it would be literally the only thing folks without Genie could get. What about DAS, does it count as a selection there? Getting a headache just thinking about the logistics haha
When they had Maxpass, it was possible for specific attractions to not count against people booking another fastpass (like Buzz Lightyear was not counted against you for a while).
So I am sure they that they could add F! or WOC as a free Genie (not Genie+) selectable option (and also have it show up for genie+ users).
Honestly, I just don't think they are going to charge for either F! or WOC (at the very least, there will be some "free" way to see the show). I could be proven wrong, I guess.
There was also mention of the Virtual Queue/Boarding Group system. I suppose that could work too.