Game of Thrones Season 8 is going to be epic, and not just because it's the end of the series. Like the beginning of Season 1, the show will open with the arrival of one Great House to stay as guests of another Great House, throwing two sets of characters together who have either never shared screen time, or who have been long absent from each other's lives. While some of these reunions are being trumpeted, one lesser-noticed meeting could be more important than all the others. Will Sansa and Tyrion end up on the Iron Throne? Though they're not married anymore, it might be in everyone's interest for them to try again.
Most fans are not in favor of Sansa and Tyrion getting back together, and who can blame them? Their original wedding wasn't about them, as much as it was about Tywin Lannister lording his power over the Tyrells. Tyrion never forced himself on Sansa, so the marriage was never consummated, which in Westerosi terms, means it never happened.
However, Tyrion and Sansa did like each other as people, and Sansa recognized Tyrion was a fundamentally decent man. It could have worked, had the Lannisters not staged the Red Wedding, which was the axe that fell between them.
But that's all water under the bridge. Tyrion is now the Hand of the Queen to a Targaryen, who Sansa's brother (erm, cousin) has pledged fidelity to (and is sleeping with to boot).
So why get them back together? Because it's how the War of the Roses ended, and the original A Song of Ice and Fire novels are a fantasy-overlaid version of that tale.
The War of the Roses was the fight between the noble houses of Lancaster (Lannister) and York (Stark) for the right to rule England (The Seven Kingdoms). This ended when the Tudors (Targaryens) came in and defeated Richard III (a Yorkist).
It also ended because of marriage. Henry Tudor, who was vaguely related to the Lancaster family, took Elizabeth of York as his wife, thereby marrying the two houses together. The Tudor rose, by the way, is the White Rose of York and the Red Rose of Lancaster laid on top of each other, to represent the union of houses under a new, neutral name.
Now, most assume Jon and Dany is the series' endgame, but what if that's not true? George R.R. Martin always zigs when fans expect him to zag. It is just as likely the two of them meet their end in the "bittersweet" conclusion, leaving the Targaryen line and the dragons done, and a new ruler to pick up the pieces. Knowing the series was based on the War of the Roses, why wouldn't Tyrion and Sansa step into the roles of Henry VII and Elizabeth of York to end the series? (She was a redhead!)
Fans know Tyrion is a smart ruler, and Sansa is excellent at the PR angles he failed to consider during his time as Hand of the King. It's not a love story for the ages, but it is the beginning of a beautiful friendship that could rebuild the kingdom once more.