Hell even on how not to overfluffify the damn thing.
Just cause we're B/S-shippers, doesn't mean we can just having Buffy suddenly fall in his arms. It might be an AU, but we're still stuck with everything up to the end of Seeing Red.
So basic stitch that we're sure of:
-Dawn is not a slayer and will never be a slayer
-Buffy is a competent leader and does not ignore Dawn
-Xander may be dead, but he's still around
-the oncoming Apocalypse is not just talked about but shown
-Tara and Dawn have conversations on Willow
-Willow is not just forgiven, she actually has to work to reearn the trust she lost after her actions in Villains, Two to go and Grave
-Caleb appears earlier
-The scythe doesn't show up out of nowhere (or it does but differently)
-The potentials are people, not just annoyances
-no Willow/Kennedy to ignore Willow's guilt.
-Dawn's being the Key is brought up and given meaning
-Webster Holden stays
-The FE actually is a threat and not just the annoying voice in the background