Finished the game for the first time, nearly lost one guy on the final mission but actually did the final assault without losing anyone. I really enjoyed the final mission, felt rather short but I liked it, Did it on modified recruit Ironman, I didn't touch any of the difficulty settings that effect tactical gameplay or the air game but settings like op points to 15 to experiment with them and stuff like that. Those 2 failed missions were terror missions, 1st was a Wraith Andron mission and the 2nd was a Cyberdrone one, but I actually skipped some terror missions in countries that had low panic because 20 panic I can recover from, losing my squad of vets and getting little to no resources out of it to recover is harder to bounce back from.
Gonna do a big write up later, Milestone 5 is very different from 4 though, I think mostly for the better. Op points seem to fundamentally change the balance of the game mostly entirely in your favour, being able to get 500k off the bat or reduce panic constantly is absolutely huge and in retrospect, 15 op points a day is pretty strong. Also end game fusion batteries are hilarious, all my secondary bases had 3/4 batteries and even if a UFO tried to assault it, it got nuked by a single battery most of the time, rarely did it survive to see the second and if it did, had below 10% health.