She's Come a Long Way
Now, as a well-known member of the Sansa Stark Defence Squad, this may seem a little biased, but Lady Stark is in her prime in the season eight premiere. When we leave her in season seven, she's just conspired with her siblings to put Petyr Baelish on trial for basically starting the War of the Five Kings and leading her family to ruins. She's flourishing in her role as Lady of Winterfell despite all of Jon's shenanigans beyond the Wall, and finally able to reach common ground with her younger sister, Arya.
In the premiere of season eight, Sansa is formidable as a leader for the people of the North and she's a well-liked one, as folks will remember the lords saying that they should have given her the crown over Jon. She's cordial but unbending, compromising but firm. And she's sassy as all hell, to boot.