Corrected entry: On both occasions in season 7 prior to "Chosen", whenever blood is spilled on the seal of the hellmouth, an ubervamp is brought out as the seal opens (e.g. when the First bleeds Spike; when the demon girl bleeds Xander). But, in "Chosen", when Buffy and the Potentials cut their hands to open the seal, no ubervamps are waiting to come out. Instead, the seal opens to reveal a set of stairs that lead them down to where the ubervamps are. That is the only way the Slayers could get to the vamps to surprise them, and the only way the whole ending with Spike could happen, but it isn't consistent with the rest of the season and what happens when blood is spilled on the seal.
Corrected entry: For most of Series 7 there is a girl from Hong Kong among the Potentials. No one can speak Cantonese and she doesn't speak any English, so how did Giles convince her to get on a plane with him and fly to America? She wasn't sent by her watcher - Giles states very clearly in 'First Date' that she never had a watcher, and in 'Potential' Buffy mentions to the others that 'Giles has gone to Hong Kong to find the Potential there.'
Correction: There would obviously be people in Hong Kong who could speak English and explain everything to her.
Corrected entry: In the episode where Spike is having memories of his mother, he tells her that Drusilla made him what he is (a vampire), telling us she is his sire, but in series two we find out that Angel was his sire.
Correction: The other episodes, the "First" planned the openings. They guided the people there. And there was a bit of a ceremony, maybe to call an ubervamp to the seal. But, in "Chosen" Buffy and the potentials took the fight to them. The opening was their plan, not guided by anyone or anything.
Rlvlk