Unfortunately, it will eventually come; however, I wouldn't expect it to look much like it does now. There are too many locals that go on a regular basis and the system as it stands now would never work.
I think in the end, it will work like this:
- FP+ may only be obtained day of
- You may get three upon entering the park
- You may get a fourth after your third has been used or has expired
- You may get additional after the latest one has expired, one at a time, based on avilability
- You can get FP+ from the kiosks or your phone, but again only the same day.