I agree they're trying to reach a happy medium for both kinds of guests as you have described.
A concern of mine is that if some guests haven't got a clue how to get a FP or, how it works and that it is free, this whole new experience could overwhelm them. I'm sure Disney will market/advertise this well, like they have with regular FP, but some guests will remain clueless and will be most likely reporting back to surveys with the same feedback as the one posted about guests' 'terrifying experience'.
If there is going to be an 'x amount of days' you can pre book in advance, will the people who like to sleep in be able to get up and be ready to get their desired times? Some will, some won't.
If FP remains operational when FP+ rolls out fully, even if for a short period, would there be anything to stop a family using FP+ to pre book evening times for attractions at DHS, and buy 1 day non park hopper tickets that they could use at RD for DHS to use regular FP?
If the family were staying at say, Beach Club, this could easily be done.
Can Disney prevent that at all? If the 1 day ticket was paid with the same credit card used to buy the RFID tickets/magic bands/package, is it possible the sale couldn't be made to that family?