I don't think it's fair to compare Universal 's EP with Disney's FP+. Yes if you are off site you pay at Universal, but you are getting front of the line access for all rides except Harry Potter attractions. FP+ is allowing you to reserve 3 rides in advance.
If Disney was offering the same as Universal, I would be willing to pay $50/day extra (I realize this would be impossible). But I would not pay $50/day for 3 FP+attractions.
Then we can amend to make it more like US, it is good for one return time to everything except TSMM, 7DMT, SOARIN, and A&E...unless you are on-site.
The point is, right now, the biggest complaint (other than the loss of FP legacy loopholes for cheating the system) is that you can't get all the hottest ticket rides at the perfect times.
By being nice and offering the service free to all attendees (unlike all other park companies that rake in the money on them...Six Flags it is $100+ per ticket, per day

) they have created the problem where not everyone that wants a FP for a ride can get one.
I didn't get one for HM on our last day (the day it reopens after the refurb) but I am not calling for flaming barrles of oil to be launched into the park, like some who didn't get an A&E FP. I totally get that there are limits...they either need to limit WHO can use the system, or limit the numbers at each ride...as an on-site person, yeah, I would prefer them to limit the WHO to US. But since that is not their plan, I'm ok with getting a jump on the offsite people....didn't used to get that before, except for morning EMH...which were only good for that reason.