The bottom line here is: we're fighting the undead. There's no way to use actual battle tactics on them because the only "strategy" an army of this size is going to follow is launching as many bodies at their enemy as possible, no matter how many they lose. Need a bridge made of bodies to create a safe passage through the fire trenches? No problem. Life is only precious to the living. We got a really nice bit of straight-up monster house horror with Arya creeping around the halls of Winterfell with the dead on her heels, and a very cool moment with Melisandre where she reminds her of all the eye colors of her enemies Arya's going to snuff out. There were lots of cool moments -- Beric Dondarrion's heroic death and the dragon dogfight above the clouds were highlights -- but the end result felt weirdly lacking.
That's probably because we're only midway through the final season of a show that has no interest in picking apart a lot of interesting things. It's frustrating to be bored by big-budget dragons and undead armies and cryptic prophetic sayings, but the true threat, even after all the lore building and theorizing that went into building up this huge event in our minds, was never the Night King. We have four hours to go before Jon and Daenerys and Arya and Sansa and Tyrion and Jaime and Brienne and Grey Worm face their final threat, and Cersei's only one human woman. She doesn't even have any elephants.
The point (rather, the point the showrunners are trying to make here) is that Game of Thrones was never about mystical magic and fire-breathing dragons and prophecies and flaming swords, though it has plenty of that stuff. In Westeros, everyone is only working towards their own interests, which are rarely ever as noble as Saving The World. You can sacrifice yourself to save someone you like, or turn into a raging tyrant to protect your family, or murder people simply because you enjoy it, but these are all very human concerns. And humans spend a lot of time making mistakes. Game of Thrones began with a very small mistake (the murder of Jon Arryn) that launched everything else into motion, and there's a chance it might end with a very big one. It might be disappointing, or anticlimactic, or brutal, but in no way would it be a departure from the root of the show. Game of Thrones now has three long episodes to try to make that work.