If Buffy had died while Faith was in a coma...they wouldn't have called on another Slayer?? I mean, according to the tradition it would've required Faith's death to bring the next one along.
But then again, they don't really follow the Slayer "rules" anyway and whatever they do doesn't follow logic. Like, Kendra and Faith were good and experienced as a Slayers when they were sent to Sunnydale though it was long known that Buffy was alive after all. And even with those duos happening they still took five more seasons to realize that hey, why not make all the potential ones active and thus be more efficient.
Also, judging by the potentials in the last season, they don't care enough to actually train the potentials BEFORE they're activated even though for some reason they are given watchers and knowledge beforehand.
Aso, the famous bit "to every generation is born a Chosen One", she alone can..:" - Yet apparently every generation has a whole bunch of chosen ones - that is completely contradicting the scripture, and they exist long before the previously active Chosen One dies and at points more than one of them were together - as in no one is actually the onlly one capable in any way.
It's a great series, I love it, but it surely would be so much stronger if the very premise wasn't this full of contradictions and lack of logic. It could've been written much better in itself. This remarkable sloppiness of writing has lessened the series' shine for me.
But I anyway enjoy it mostly for its hilarious, interesting and witty dialogue, and some brilliant characters and relatiosnhips such as Buffy and Giles.
But "Angel" the TV series is so much more pulled-together about its premise and more "grown up" with its darkness and themes, and thus somewhat better as a whole. Yet I still end up watching Buffy the Vampire Slayer" more often because of the dialogue and relationships between some of the characters.
In my opinion;
As a whole & premise: "Angel" wins.
Dialogue and character relationshios: Buffy the Vampire Slayer wins. The only relationship that really interests me in "Angel" is that of him and his son Connor.