I agree with TheSlayerofLies that Sansa's arc is not about becoming queen and that "playing the game of thrones ≠ being queen." Besides, the "rules" of the game that she learned from Littlefinger, Cersei, etc. may no longer be very useful or relevant after the wars that will take place in Season 8--especially if Dany or Jon or whoever ends up ruling decides to "break the wheel."
"She was preparing the country for winter, making sure the castle was protected, and that her people had food and warm armours" (quote from prettylongclaw): She was preparing Winterfell and the people who lived near it for winter, not the country. This is something any efficient lady of the manor could and should do. It doesn't follow that if Sansa does this efficiently, then it's a sign that she's on her way to becoming queen. Same goes for her appeasing the lords of the North. There just isn't enough convincing evidence that her arc is about becoming queen.
Moreover, if her arc had been about becoming queen, I think she should have accepted Cersei's invitation to join the meeting at Dragonstone in the last episode of Season 7. She could have overcome her fear and mistrust of Cersei and used this as opportunity to interact with the other major players. Instead, she sends Brienne in her place.
If Sansa is to rule or be in charge of anything, I think it's most likely to be Winterfell.