Why should Disney be obligated to provide a "level playing field" for off site guests versus on site?
I don't really understand the folks who argue that it is so much better value to stay off site and that people are fools to waste their money to stay on site, but then get annoyed if Disney gives on site guests advantages. Well, duh, Disney wants to make it more beneficial for people to pay their high resort rates and stay on property.
Now, Disney has come out and said that everyone will have access to FP+ once it is fully rolled out. It is certainly possible that on site guests will have either earlier access to FP+ bookings or might be able to book more FP+ per day (or both). If they do that, then it would provide another advantage/perk for staying on site. At that point, people will have a choice (just like they have had pre-FP+): stay on site and get the benefits of that option (free transport, proximity to the parks, EMH, free parking, early access to dining ressies, whatever FP+ perks) versus the benefits of off site (cheaper/larger accommodations, potentially nicer decor and amenities)