I was cool with it, especially as they Back to the Futured themselves into the earlier movies which was fun (even Dark World). Of course, not undoing the snap back to its origin - thus saving Stark's daughter - meant that they created a whole heap of heartache and trouble for the snapped and unsnapped alike.
Imagine coming back after 5 years - not having aged a second - and trying to piece your life back together that you didn't know had been gone! Imagine getting back friends, family, husbands, wives, kids, when you are 5 years older and have moved on to make a new life for yourself without them! How many of the unsnapped killed themselves in grief and horror at surviving? How many of the snapped will kill themselves because they cannot deal with where their world is now? How is Spider-Man: Homecoming going to deal with all this?*
* By the looks of the trailer, not at all, which is the tangled web they weave when first they practice to time travel.
Imagine the resource crunch caused by instantly doubling the population after 5 years of adjustment to the lower demand level. Half the oil production, half the electricity production, half the food production. We’re talking mass starvation here.
And what do you do with housing? Sure, there’s a lot of empty houses. But there was probably a lot of post-snap movement from shittier units into nicer, empty housing. So the units immediately available to the unsnapped probably won’t be the ones they lived in, and they’ll be way worse to boot (lower end of the market *plus* five years’ dilapidation). Does title to everything just revert to the previous owners? And goodness, what about snapped renters?!?
Way to go, Avengers. You had limitless power, and you used it in the worst possible way.