I like the theory that it was HR and not Iris that died (the holographic tech, feeling useless, responsible for blowing it, etc), but how does that work? HR was on our Earth and blew the secret of where Iris was hidden. Savitar pretty much goes straight there and gets her. Not really any time for him to swap places, and Cisco would have had to have been in on it (if Flash did it, Savitar would know).
As we've already mentioned, there's a point where Savitar lets Iris drop to the ground and the camera stays off her for a certain length of time while Barry is firing the bazooka. It's possible she was swapped out for an impostor at that point, though as I've said, it's hard to see how that could be done without anyone noticing.
Different question: can Barry create a time remnant of Iris, and let Savitar kill that instead?
I suggested that in a spoiler box a week or two ago, but Barry didn't have time to create one, the way things worked out.
It actually changed in some pretty big ways.
Yes, obviously, but not in a
critical way. This is fiction. The writers aren't forced to follow some external logic; they decide everything that happens, so they decide what changes are critical enough to prevent the change. This is a commonplace trope in many time-travel stories, including
Terminator: The Sarah Connor Chronicles, Continuum, 12 Monkeys, Timeless, and of course
Legends of Tomorrow in season 1. Naturally, in a work of fiction, you want to make it possible but difficult for the characters to achieve their goals. So you establish that only the
right changes will be critical to making the change that the heroes or villains are trying to achieve. There's a momentum to history that's hard to overcome -- "Time wants to happen," as Rip Hunter put it -- so most changes will only alter the small details but fail to prevent the key outcome. You have to change the the right critical factor -- or make enough smaller changes that add up -- in order to bring about a fundamental change.
There is a certain logic to this. Most events are the result of many factors interacting, so removing one factor may only alter
how the event happens instead of keeping it from happening at all. For instance, in T:TSCC, the characters were able to alter when and how Skynet emerged in the future, but not prevent it from emerging at all, and in
12 Monkeys (the show), they were able to change some details of how the world-destroying plague happened and create a future where some individuals had different life histories, but still didn't prevent the plague. If multiple different causes add up to bring about an event, you might have to change many or all of them, rather than just one. Or you'd have to change the right one, the one that's more important than the others.