What Twist Would You Like To Have Seen in the Later Seasons of Buffy?

I would have had it revealed that the council have the ability to make more than one Slayer at a time and that they have lied about it to control the Slayers. If every girl thinks she is the only hope then she is willing to sacrifice herself for the 'greater good'.

It would also be a better explanation for how Kendra and Faith existed alongside Buffy than Buffy dying for a few minutes and shown the council to be detestable for not valuing the girls they sacrifice.

The ending would still be the same with Willow using a spell and the scythe to activate dormant Slayers but you could have had it built to over the season and given Willow and Giles something important to hunt down after the council were destroyed.

It also leads into a new future where Slayers are in charge of their own destiny and not Watchers.