I believe that overall the fastpass system is great. For my upcoming trip from May 22-May 29, (yes I know its over Memorial Day which is not ideal, but this was the only time we could go, and I wanted to hit WDW one last time before Galaxy's Edge opens) we have FP's for all of the major attractions such as FOP, Slinky, SDMT, etc. The 60 day window for on property resort guests is obviously the only way to get FP's for certain attractions like FOP unless you get lucky. I went in October 2017 on a solo trip and stayed off property with a less than 30 day window as it was a spur of the moment trip. Even though I did not have all of the most sought after fastpasses, I still had a blast and was able to ride all of the rides that I wanted to except for the Navi River Journey. I ended up waiting about 90 minutes for Flight of Passage by getting in line a few minutes before park closing.
However, I still wonder what waiting times would be like if there was no fastpass. I understand that having fastpass may drastically increase the standby wait time depending on the ratio of FP to Standby and other factors such as the ride being down during the day. I do believe they are making the correct decision by not having fastpass in Galaxy's Edge. I remember visiting Disney Land in 1995 or 1996 when Indy was brand new. This was in the pre fastpass era, and I remember waiting 3 or 4 hours to ride. Granted I was only 6 years old at the time, so anything over 30 minutes felt like an eternity.
I still definitely believe that having the fastpass system is better than not having it, but it is an interesting debate. I agree with what some of the previous posters have said in that the best way to tour the parks is to lengthen your number of days so you have more FP's. However, I know this is not always possible.