Game of Thrones has spent more than six seasons now building up to the breakout of the Great War between the people of the Seven Kingdoms and the White Walkers with their dead army invading from the far north. While the lords and ladies of Westeros have been squabbling amongst themselves, the White Walkers have been preparing, planning, and moving south as winter approaches. Now, winter has come to Westeros, and the Great War will break out sooner rather than later. While most of us are naturally going to be rooting for Jon and Dany and everybody else to defeat the White Walkers as quickly as possible, the story would likely be much better served if the White Walkers are the winners of Season 7.
The Seven Kingdoms is utterly unprepared to face an invasion of magical creatures from the far north. The realm has been ravaged by years of civil war, and significant houses like Tyrell and Martell and even Frey have been extinguished. The majority of the kings and queens and claimants are more focused on each other and the Iron Throne than they are on anything in the North. Nobody aside from Jon Snow and Co. are preparing for a war against creatures that can't be killed by conventional weapons. Most of the people in the realm consider White Walkers to be as fictitious as grumkins and snarks. The people and the leaders simply aren't prepared to mount a good offense against the army of the dead. They'll be lucky if they can manage a defense.
Of course, Jon Snow does have an ally of sorts thanks to Tyrion Lannister's interventions on his behalf to Daenerys Targaryen. While she doesn't quite believe Jon's claim that there are White Walkers and wights preparing to attack the Seven Kingdoms, she was willing to compromise enough to let Jon mine the dragonglass beneath Dragonstone to use as weapons for the Great War. That said, the dragonglass might be too little too late, and Dany's forces are not prepared to fight a war in the ice and snow.
Dany's forces -- those that haven't been killed or stranded thanks to the efforts of Euron Greyjoy, that is -- are ideally suited for fighting in the southern parts of Westeros, and everybody seems to agree that she could take King's Landing easily with her Dothraki and her Unsullied. The problem with directing her forces to fight in the far north rather than the far south is that none of her forces are built for the cold. The Unsullied, as brave and conditioned as they are, are accustomed to fighting in light armor in warm climates. Dany's Dothraki can rape, pillage, and plunder just about anywhere their horses can run; they're not suited for a day trip to the North, let alone a mounted campaign against magical invaders.
Dany's dragons might not be enough to turn the tide in Jon's favor if she does join him in earnest. Her advisors have pointed out that there is grave danger in Dany flying into battle on the back of a dragon, and nobody else has been able to control them or ride them since they started getting big. Even if Aegon the Conqueror was able to take the Seven Kingdoms with his three dragons three hundred years ago, he wasn't doing it while fighting the people of the realm and an army of the dead at the same time. Besides, if Cersei has her way, she's taking out at least one of the dragons in Season 7. There simply may not be enough time for Jon to win allies and prepare them for the Great War before the whole thing starts.
Then, there's the reality that the only thing that stands between the army of the dead and the folks of the Seven Kingdoms is the undermanned Wall. Even with Tormund and his wildlings manning some of the neglected castles of the Night's Watch, there's an awful lot of ground to cover, and the magic that has protected the Wall for generations might not be entirely intact anymore since Bran -- touched by the Night King in Season 6 -- passed through the tunnels. The opening credits of a Season 7 episode also hinted that the winter might be cold enough to freeze the waters beside the Wall; if enough water freezes hard enough, the army could simply walk across the ice and around the Wall. That said, the odds are pretty good that the Wall is coming down at some point, and not just because Jon left Dolorous Edd in charge.
From the very start of the series, the Wall has been touted as something that must be protected. We've heard it repeated throughout the years that the Wall has stood for thousands of years. The Wall has basically been labeled "MUST NOT FALL" all along, which means one thing: the Wall is probably going to fall, and what passes into the Seven Kingdoms will not be good for the people. The Wall is the first and greatest defense against the White Walkers; if it falls, it will be a mad scramble to try and prepare for war. In fact, the White Walkers may be considered the winners of Season 7 if the finale simply ends with the Wall crashing down and the invasion only just beginning.
The White Walkers have a big advantage as well due to the fact that their army is already dead. They don't need to rest or be fed or protected from the elements. Perhaps more importantly, the army can replenish with every living person who dies, and the same can't be said for the various armies of the Seven Kingdoms. Even if Dany roasts the majority of the wights on the back of Drogon right off the bat, all it will take is a single surviving White Walker for a new army to gather. The valiant warriors of the different kingdoms will need to learn how to fight these new enemies, and there's not time for that in what's left of Season 7.
Truly, the White Walkers have pretty much every advantage. The dragonglass weapons will be helpful, and we can only hope that Dany finds a way to lend her dragonfire to the fight. A few swords of Valyrian steel could go a long way if they're in the hands of skilled warriors like Jon and Brienne. Still, the humans have to deal with the normal troubles that will come with surviving a winter on depleted resources, and those are already threatening the lives of folks in the North without the Great War on their doorsteps yet. There's no doubt that the people whose journeys we've been watching for the past 6+ years are capable of finding a way to fight, but they'll have to find an advantage or two first. Winter has truly come.
Finally, we have to take into account that only one season of Game of Thrones will be left after Season 7. This batch of episodes is the second-to-last act in the saga, and the stakes need to rise higher than ever before. This is when Luke Skywalker gets his hand cut off and Han Solo is trapped in carbonite. This is when Dumbledore goes down for the count. This is when the Joker has rigged the game, killed Batman's lady love, and created Two-Face. This is when the good guys suffer a devastating loss so they can come back with a vengeance in the final act. Season 7 is the time when the winds of winter truly pick up so that the survivors can dream of spring in Season 8.
Admittedly, Game of Thrones is known for subverting expectations when it comes to fantasy sagas, but that's not always the case, and this is a formula that has been proven to resonate with audiences for decades. If we want a totally awesome Season 8 that leaves us satisfied and not necessarily chomping at the bit immediately for those spinoffs, Season 7 shouldn't end with the good guys on top. The White Walkers should win so Azor Ahai can have his (or her) day in Season 8.