Actually I quite agree, after having watching this season again recently (currently on 7x21). What would have been a better twist is if we don’t see Shannon’s rescuer during the attack and “savior” by the bringers, and instead get an off camera distorted audio (to keep the reveal later) in the same vein as what was written.
Earlier in the season, it was established that the Scoobies were having difficulty locating Wood’s past (
First Date) and how he became principal of Sunnydale High. Literally nothing was available to resident computer hacker, Willow, after Wood came to Sunnydale.
He then explains:
Well, I actually do enjoy the work, but yeah. Yeah, you're right. I maneuvered myself into that school, that office—just like I maneuvered you there. The hell mouth draws the bad things in close, and now we're headed for something big, Buffy. Really big, and I need to be here when it happens. I want to help.
This is an excellent set up for infiltrating the group. After Wood works with Buffy during “First Date,” he’s become fully infiltrated into the group, as she shows him their set up in “Get it Done”. The First talking to him at the end of “First Date,” where he indicates who he knows is speaking could also be red as anger that the First is using his mother as its anchor to speak with him. Then, in “Storyteller,” we get a “possessed” Wood speaking his inner truth about Buffy and Spike. He shakes it off. However, this sets up the events of “Lies my Parents Told Me,” where it could easily be explained in retrospect that Wood had dual motivation: help the First and kill the demon that killed his mother. Between these episodes, Wood still seems like he could go either way. He isn’t exactly a part of the group, and he’s shown that he
can be an ally. He has shown he has some kind of strength when fighting the vampires and other worldly beast with Spike.
Narratively, flipping this on its head in the very next episode, where instead of meeting Caleb at the Vineyards, it’s Wood standing there amidst the attack of bringers, and it’s revealed it was him setting up all the background commotion all along. This would have fit so much more naturally. And it would in a way parallel the rebel Slayer story from season 3. Wood started out as good, but the death of his mother haunted him for years to come, corrupting his morality like the First corrupts the morality of those who do good for its bidding.
Then, having Wood finally make the decision to infuse himself with the essence of the First in 7x21 would be a massive payoff to the buildup of the season. After having been rejected by Buffy due to his personal vendetta against spike, he finally succumbs to the temptation of the First. Mirroring the Garden of Evil story in biblical mythology.
It would also give an actual way to end the season’s arc with a physical threat. The First now manifested inside of a true, willing vessel that we have seen teeter between good and evil for multiple episodes. Even through in an attempted redemption arc with Faith at the hemp during “Touched,” where Faith attempts to bond with him and rescue him from that temptation, paralleling her own arc in the series.
Obviously it doesn’t help. Wood and Buffy initially face off in the vineyard, and she gets the Scythe as in the original plot. No Guardian because that was absolutely pointless. And no hordes of Turok Han, though multiple are raised to create extra chaos, as The First/Wood attempts to open the mouth of hell permanently, paralleling the Season 1 finale.
Willow still uses the Slayer spell to imbue those Potentials in the high school—who accept their destiny as Slayers—disrupting the line until all who were given the choice eventually die off, setting up the ability for the line to continue in the future as it normally would.
The power of the Slayers together permanently closes the Sunnydale Hellmouth by the same sacrifice of Blood that was used in the show to open the Seal, and so they must face only the Turok Han whom First/Wood allowed to escape prior to this permanent closure. With the added bringers and the First in Corporeal form as Wood (it’s willing vessel—also paralleling the very first episode
Welcome to the Hellmouth/The Harvest), Buffy and the newly powered slayers still have their epic battle, but when they realize they are becoming overpowered and too many of their allies are falling to the Turok Han and Bringers (Amanda, Anya, other nameless Slayers), they go to plan B. The Scooby Army gets out of the school, save for Buffy and Faith, who are the last original slayers fighting Wood/First. Once the all clear is made, they duo power kick Wood into his office (directly above the Hellmouth) where the windows have been boarded up and gas canisters have been laid around the room (in homage to the season 3 finale).
Buffy grabs a grenade out of her stash, tosses it to Faith to do the honors, who unpins it, tosses it into the room, they slam the door shut and run like hell to jump on the bus leading out the school grounds (similar to the finale we got).
The First/Wood blows up, along with the school and Hellmouth (again). Xander quips that maybe this time they should leave the school in ruins.
There’s still around 30-40 slayers who now share the responsibility of keeping evil at bay. Buffy still has her choice to retire and let the next generation keep fighting. But her home is still in tact, and she can continue being Sunnydale’s guardian—if she chooses. And if not, Kennedy (with some support from Willow and the gang.. and who I actually liked this time around?) can continue the fight in Sunnydale, (as we know the Hellmouth is never
really closed) while the rest of the new Slayers go back to their towns or countries to continue the fight on their own turfs, building their own Scooby families along the way.
This version averts Spike saving the day, keeps the female empowerment of the episode and series, while also using a character that the season had been building up since Lessons as a main baddie instead of some random 5 episodes before the finale.