I know I'm not expressing myself well here so I am about to give it up, but one last try. The people that will be "sleeping in" because they already hold FP's were and are, at the present time, the ones that are there at opening and taking FP's at that time. The number of guests at WDW are not going to magically expand by huge amounts. Many of the rides will be walk on because those folks are staying in bed longer leaving the park for others. I don't see it as being an end all. Other advantages will show up.
Those people were taking FP's anyway...they will have them earlier now, leaving the kiosks less crowded and available for others. Disney would have to be out of their everlovin minds to reserve all FP's just for Resort Guests. The times may not be always ideal, but since the load capacity cannot change, they cannot expand the numbers of FP's available. Also, many will, in all likelihood bypass the preset FP simply because it is way to damn hard to figure out when you want to ride a ride that far out.
I guess, that I just feel that since we have so little information about what is going to happen, panicking about it now is just a waste of time. We will know when, and if, it becomes a reality. Until then...nothing has changed except the enforcement of the Window times.