A prediction, based on nothing more than uninformed speculation.
Disney will announce the return of Fastpass+ as soon as the CDC relaxes the social distancing guidelines. The system will, on paper, be the same as it was in the before times: 3 free fastpasses per day, tiering in some parks, the possibility of subsequent fastpasses after you use your first three, advance booking at 60 days for onsite and 30 days for offsite, etc.
But Disney will also simultaneously debut paid fastpasses. These will be anytime/any ride/any park fastpassess--rather than being limited to a particular ride during a particular time window. (There may be a limit on using more than one of them on the same ride. But I hope not.) These will be sold in packs of 3, 6, or 9. Good for one day only, and not transferable from one guest to another--just like an anytime fastpass in the past. The cost will be somewhere around $59 for 3, $109 for 6, and $149 for 9. (That's per person, per day.) They will be available for purchase in advance, beginning the same day that you can schedule your regular fastpasses. Disney will limit the number for sale for each day. They will probably sell out early for crowded days.
Because of the presence of these paid fastpasses, the days of scoring headliner fastpasses, after using your first three, through the refresh method will pretty much be over. Or at least it will be a lot harder to do. Disney will be very cautious in releasing them--or even making them available to someone else after a cancellation. And it might also be even harder than it was before to score a free fastpass for a headliner in advance, since Disney will be well aware that the vast majority of these paid fastpasses will be used on the e-ticket rides.
If the CDC does not relax the social distancing guidelines by the summer, Disney will go ahead and debut the paid fastpasses without yet restoring the free ones (but announcing an intent to do so when the guidelines are changed).