Avengers: Endgame - Everything That Changes If The Heroes Steal The Infinity Stones From The Past

6. Hela Remains Captive, Asgard Probably Doesn't Fall

Though Marvel fans might have wished that Thor: The Dark World was wiped out of existence entirely, Thor: Ragnarok actually depended quite heavily on it as a narrative launching point. And specifically, it depended on the climactic battle, which itself depended on the important role played by the Aether.

Without the Aether, there would have been no battle between with the Dark Elves, without the Aether, Frigga would still be alive and Loki would not have joined the fight, and without the Aether, Loki would not have been able to feign his death to replace his father on the Asgardian throne.

The key here is that Loki taking over Asgard is what ends Odin's life, effectively, which is what frees Hela and leads to the fall of Asgard. She wouldn't have been able to claim her kingdom back, Odin's memory would have been preserved (well, the lies would) and the Asgardians wouldn't have been cast out into space.

Which means they wouldn't have then been even further massacred by Thanos at the outset of Infinity War. They are a troubled people. So maybe the Avengers stealing the Reality Stone before Jane Foster gets her hands on it maybe WOULDN'T be the worst thing.