Neither Sansa nor Bran were King/Queen of the Realm material. At least not how it played out on the show. At this point, it is what it is. Personally, I think Sansa's character arc has been lacking since the marriage with Ramsay storyline. Based on what I've seen on the show, this is all she did since then:
Season Six: Pouts, moans, and bitches to Jon about taking back Winterfell, her home. When Jon, Sansa, and Davos tried to get Northern forces to fight with the Starks few were willing to follow Sansa. The ones that did followed because of Jon and Davos persuasion or because they had suffered under the Bolton's. She nitpicked everything Jon did but didn't really offer an valuable advice, other than "don't do what he (Ramsay) wants you to do". Apparently, she had already written Rickon off as a goner but failed to mention that to Jon and instead then used Rickon to play at Jon's heart strings some more. She also failed to mention that she was apparently actively working her connection with Littlefinger to try and get more men to fight for the cause. Jon was then left to fight with what he had until The Vale showed up to save the day (which Sansa never let anyone forget) and after untold numbers of Northmen, Stark Bannermen, and Wildings had already been killed on the field of battle. And that's just everything leading up to BoTB.
Season Seven: She reminded everyone to send food to Winterfell and apparently needed to tell a seasoned commander that his soldiers needed plating because it's so cold in the North. And she whined and complained about Jon being gone, while he was out trying to get resources to fight the AoTD. She was played by Littlefinger for the entire season and he was turning her against her sister.
But I'm not even mad that she's Queen in the North. It's what she been wanting probably since the BoTB. So props to her for getting it.