We can't have it both ways. If Sharon is a nobody, someone that means "zip" to Steve, then why make such an effort to set them up in TWS? If she means something to Steve, then she means something.
Included in the vision, Sharon could have represented hope, Steve's future, and an overdue reality check for Steve's lingering feelings for Peggy. It isn't Atwell's fault that she keeps being included in the MCU, but it is Marvel's. Her continual presence is a roadblock for Steve/Sharon. Family ties aside, we've seen that Cap can't seem to shake his 1940's flame.It'll be sad if the only thing that causes Steve to move on with his life is Peggy's death.
Yanno, I'm just naive enough to believe--expand my belief, that is-- that Steve's issue is that he can't move on in his life because the chasm he crossed from point x-1945 to point y-2011 (or whenever) was just too traumatic to adjust to fully. It's not alll about Peggy. There will always be the question of what is Steve's place in the world.
That may have been a character trait that is hardwired to the character
as I see him. Even Skinny Steve, while bravely getting through life, losing both parents (apparently never knowing his father per MCU cannon), not getting the girl, initially denied the opportunity to validate...to prove his manhood and his humanity by a 4F rating, that Steve Rogers was having a crisis and couldn't move forward except through a war. He wasn't the least excited about dancing with the surplus of eligible women resulting from the war and decided to put all that off until after.
It was the end of the war and Peggy that symbolized his future. It was the loss of that and everything else he knew that has him blocked in the present.
Now he seems well-adjusted to technology and he's got his little pop culture list and he no longer dresses like the "greatest generation", but it still seems clear that he's in a world that is bewildering enough that he bravely gets through life one mission at a time, denying himself female --romantic -- companionship with the exception of his bedside friendship with Old Peggy. (As far as we know because you JUST KNOW that he would get propositioned on a regular basis. So...opportunities...just sayin')
He mourns what might have been. Yes, that includes Peggy, but also coming home, building a life in a time he knew and understood, seeing time and events unfold (the good and the bad) in what would have felt like a natural progression.
Now...
Anybody can fall in love at any time. Even comic book super heroes. And I accept that Staron is bound to happen because the stage has been set for adapting the relationship from the comics. We'll get Sharon just like we got Bucky and the Commandos and Sam and Red Skull and Zemo, etc. But it will not be the Staron that everyone who is a fan of it might want because it will be adapted and shaped by things that have preceded it in the MCU, just like every other character adaptation. I also doubt there will be a white catsuit involved.
The entire on/off cycling of their comic book relationship might be carried out to its logical conclusion over the course of this one movie. Or it might be a precious new beginnings arc to be continued over the next movies. I doubt the latter though because this train is moving kinda fast...they need to get to whatever they plan to get to.
Yes the Russos planned to use the character for some time now. It remains to be seen how the character will be used. Will it be to provide love/hope/happiness for Cap or to test his will/resolve/character in some way?
But, I have to say that when Peggy dies, it won't be a closure; it'll just be one more loss. Old Peggy was his friend. He may not have gotten the passion, but he got to live out the friendship. That was, to some degree, the closure.
also I hear some people say that Fitz/Simmons is like Steggy 2.0 at the end of S2 people were saying but they had a date like Steggy!, I agree there are some parallels between them. Also [BLACKOUT]Hank is going up against Hydra in that flashback, something tells me Cap will be mention.[/BLACKOUT] 
t:
But not a lot of people are shipping Bruce, Thor, and Hawkeye.
