My biggest complaint is I think the 60day window is a mistake. The window should be very short IMO - less than 7 days.
Yeah, I think that the window is one of the main problems with FP+. If it was "the night before", there would be a lot less complaints about that area. We don't do table service, so don't have any ADRs to make at 180/190 days out (we only made 1 ADR last time - TREX, and it was the worst meal that I had all holiday - it was inedible.)
Another one is the wristband (it's fine if you're going to be there for a day or two but if we go for a two or three week holiday from the UK, given that we're not going to be tanned, is going to leave a noticeable tanline, and be annoying to wear for such a long time, and if we don't wear it, it's going to take up more space in a pocket than a ticket would.)
Another one is that you can't get more than one FP+ for the same ride on the same day, and for example, you can't get TSMM/RnRC on the same day - it's more restrictive than the current setup - I understand why it is how it will be, but it doesn't make it any less annoying. As I have already said - we got 18 Fastpasses on our last holiday, based on the current FP+ setup, we couldn't get at least 3 of them, and we didn't need them for the other attractions.
And I don't mind the rush to TSMM, Soarin' or Everest - last holiday we were up at 6am, asleep at midnight every night for 3 weeks - it's not like we're going to stop that because we can reserve Fastpasses ahead of time - it just means that we're going to be able to ride the main rides less, and the queues for the smaller rides will be longer.