Which wouldn't work in the MCU. Because then that would make Sharon a Black Widow clone. Because Black Widow came into the MCU first with that personality and dynamic.
So having her in that role in Winter Soldier was the best choice from a storytelling standpoint.
Black Widow didn't have a dynamic of any stripe with Cap before TWS.
And she's hardly the only cynical pragmatic spy in fiction.
First you say the Russo's cut Sharon and put Widow into her place and then you say Sharon wasn't even in the script until the Russo's put her in there as Steve's undercover neighbor.
Which is it? Both of those things can't be the case.
I didn't say that

I said that "Kate" was originally not Sharon.
That means one of two things;
1) Sharon had a different role that was cut.
2) Sharon wasn't in the script at all.
Which despite the fact that
a. the movie is full of SHIELD and SHIELD agents and Sharon is a SHIELD agent, a major Captain America supporting character.
b. Peggy, who in 2009-11 (the period TFA was developed in), was pretty irrelevant as far as WWII Cap love interests went aside from the fact that she's related to Sharon, was put in the movie as a main character. Even though movie Peggy is much more similar to Cynthia Glass and Betty Ross than she does with Peggy Carter.
c. That M&M have talked about wanting to use since the 2011.
The comic book continuity is NOT the MCU continuity. I don't care how salty that makes you, its still true.
I don't think you care about how irrelevant it is, either.
Comics not being the MCU means that things can be changed. It doesn't mean that any change is beyond discussion. Or that change for the sake of change
What sense would it make to eat up a ton of screen time to establish Sharon as a seasoned SHIELD agent and her relationship with Steve when they could just drop Black Widow in and use her established place in the MCU as shorthand (and Scarlett Johansson is already under contract) and hit the ground running? Pacing is important in movies.
1) Natasha doesn't really have much of a relationship with Steve at the beginning of TWS. The relationship forms
during the movie.
Sure, she tries to set him up on dates, which sticks out like a sore thumb. But Steve apparently doesn't know the first thing about her, like, oh, that she's morally bendy.
2) All it would take to establish Sharon as a seasoned agent is showing her being capable in the same place Natasha is.
3) "the sense" would be that a. Sharon would be someone new, who Steve didn't know well and didn't know if he could trust, which is a major theme in the movie.
and b. Because then you have Sharon as a fleshed out character, which makes it easier to carry out future storylines with her and Steve.
But lets look at Sharon's treatment in the movie again.
Nick Fury assigned her to watch over Steve Rogers. This is obviously an important job to give to a SHIELD agent, looking after the "greatest soldier in history" as Fury called him. And she got the job. So obviously Fury has great respect for her.
And in that capacity she did nothing at all.
She acted heroically when Crossbones (a highly trained dangerous and more experienced fighter and one of Cap's biggest enemies in the comics) was trying to intimidate people in the control room into launching Project Insight.
So did a nameless SHIELD technician, and a room full of nameless SHIELD agents.
And then she heroically was knocked on her ass with zero effort from Rumlow.
Black Widow respected her enough to think she would be a good romantic partner for Steve.
If I walk up to you and say you should to vote for XYZ for president, and then I walked away, without explaining what party is XYZ or what is XYZ's stance on immigration, health care, security, etc.
Would you feel compelled to vote for him/her?
How is any of that a disrespectful treatment?
The part where she went from major character who is experienced and capable to a minor character who is inexperienced.
Given that the movie had Black Widow and The Falcon and Nick Fury as major supporting characters eating up a lot of screen time (and big stars playing those characters)
The "big stars" argument needs to stop. The Russos hired her. They can't say that they didn't want to spend time on EVC because she's not a big star, and it is ridiculous to invoke that poor excuse on their behalf.
Sharon got a good role in the movie all things considered.
"Good role" is in the eye of the beholder, apparently.
Sharon got a role intended for a bit character, by their own admission.
She literally got the same treatment as a character not intended for anything and never expected to appear again.
And she was set up for future movies going forward, to expand her character. Why would the Russo's set her up as a future love interest for Cap if they didn't want to use her?
Where are these future movies? They keep talking about Iron Man, Spider-Man, Bucky, Black Panther, Peter Parker, Black Widow, Spidey, and their arcs. Nothing on Sharon.
If she gets a decent role in Civil War, I'm guessing it was in spite of the Russos.
We do know that she isn't going to be a love interest in Civil War, despite it being in the script originally per Mr. Chris Evans himself. So on she has to wait for Cap4, if it happens, because Cap is busy with Hawkeye and Scarlett Witch for now.