But Bucky is enhanced (comics and MCU) and has beaten Widow in the comics e.g. one of the post Winter Soldier comics around 2007. Widow put up more of a fight than in the TWS movie but she definitely lost. Ultimately its up to the writers.
For example, Bobbi is also an Avenger in the comics, and has had some impressive fight scenes in AOS recently so it would be nice to acknowledge more than one highly skilled spy in SHIELD. Again, in Avengers the writers created a scene where Widow fought Barton in close proximity - her strong point. If that scene had Clint fighting from a distance Widow would have lost. Sharon is a great markswoman and could take out Widow - its up to the writers how they construct the story to a characters benefit/disadvantage.
RDJ is a bigger star than Chris Evans, so should he have a bigger role in CW? Alternatively, Cap is arguably the most popular character in the MCU. The star power argument doesn't provide a good movie. It should be about characters and story.
Chris Evans is a star and a movie star and is starring in a movie about um...
Captain America. When starring in
Avengers though it's apparent (and whined about enough) that RDJ is treated as the biggest star. Whereas, EVC is not a movie star let alone a star, and the movie last I looked did not have her character's name in the title.
There isn't a producer alive that would cut out Scarlett Johansson and say give me more EVC unless they didn't want to sign a paycheck, and that's before she was even in a Marvel film or had
Lucy. I doubt there's a director that would choose EVC for talent over Scarlett either.
Add to that that Marvel wanted more film established characters in TWS since Steve had lost most of his between movies and using BW as a main supporting character was a no brainier. Her character also IMO is a far more interesting one they can do more with.
Bill, M&M have been talking about Modok since 2011 as well. It doesn't mean they've written a script for him let alone been asked to write one by Marvel. Ditto Sharon. Like Modok who they also acknowledge is a hard sell they state that Sharon's relationship with Peggy makes her a character one has to walk a "fine line with" because it's "almost to a point where you get a little uncomfortable because her relation to Peggy".
Obviously Sharon's not so great a marksman if she couldn't shoot Rumlow fast enough.

Regardless, shooting someone doesn't mean they're a superior physical fighter and that was the point some were trying to make, namely Voltron - that she should be able to "woop" BW in a fight.
This is like my saying Steve would beat Thor or Hulk in a physical fight. Liking Steve more doesn't make him stronger. Liking Sharon more doesn't make her a better or even equal hand to hand fighter than BW.
After talking about there are different kind so female strength then wanting the council woman to go all BW on people seems contradictory. That and it being BW makes for a far more economical and streamlined narrative.