Could have felt so right if only the characters in the sacrificial pairs were switched... Steve's character has always been about self-sacrifice, from the very first movie, from his very first heroic moment that led to his becoming Captain America. His whole life is defined by doing the right thing, fighting, and saving (and sacrificing if he has to in the process of saving). Don't get me wrong: I love him and I want him to get his happy ending. But the way it is done, it just feels wrong for the character. How did we get from the Steve of all previous movies, basically, to the Steve of the end of Endgame? He went back to Peggy and had a happy and peaceful life, stayed out of all major world events and injustices for 70 years. How is that the Captain America we know and love?! There is a major development arc missing from his storyline; the same way there was a major development arc missing to expalin how he finally got worthy of Mijolnir... As a whole, Steve's character was rather flat in Endgame. What did he learn? How did he change and grow? It's not that characters have to change and evolve in every episode of a series, but such development was strongly implied when it comes to Steve Rogers in Endgame, although we never see it on the screen. The whole episode starts with Tony's accusations--so that scene was just about Tony?? What was Steve's response?--and ends with his getting worthy... how? Hmmm, how did a storyline giving my favorite MCU character all he supposedly wanted leave me so empty and unmoved? I hope the Russo brothers will get to write the jumping-between-timelines explanation they have mentioned and explain what actually happened there...
Tony... After everything he's done for the world... After the glimpse we got into a happy retired family-man life for him... he deserved better. He had a plan, a family. He could have been happy without being a superhero from now on. Why couldn't he get that peace and happiness? He had grown enough over the course of the movies to finally be ready for it. I hope they'll bring him back.
Alternatively, they could have let Steve sacrifice (go back in time and take Tony's place, for example) and Tony live happily with his family... It would have been painful, dramatic, and in character. I don't buy the whole Tony-was-incapable-of-self-sacrifice "character development" argument, when he risked his life over and over again to save the world. Last time he did was in Infinity War when he was so disappointed Dr. Strange didn't let Thanos kill him.
Same with Natasha and Clint. What was the point of Nat sacrifing? If Clint had died, it would have been seen as character development and would have probably led to Natasha's further character development. Natasha's death didn't contribute to anyone's development. It was just a plot device. Therefore, just bring her back, too, and be done with character deaths in Endgame--it's a dumb trope, anyway...