Buffy gets to decide how the world should be because that is why the Shadow Men created the Slayer. To protect the non-magick beings on earth, defeat demons and monsters, and make sure that the balance never tips to the wrong side.
I'd say that Buffy has succeeded. Activating the Potentials stopped the First Evil from tipping the scales on the side of evil. However, there were so many activated that the PTB or Universe let more demons come out of the woodwork to balance the scales. And then when the Slayers were being annihilated, demons were being praised, and a floodgate of new demons were being poured in, Buffy managed to not only beat them back but to make sure they could never rise to power again.
She did more to defeat the forces of darkness with those two decisions than any demon hunter that came before her.
I think that there would have been no Chosen apocalypse if not for Willow. The First Evil found a way to rise to power because Willow had Buffy resurrected. It caused an anomaly in the Slayer line and the FE took advantage of that damage.
I think that if Willow hadn't of taken up spells, Giles would've gone back to them. He was a good spellcaster and would've been more active with it had the need arisen. He managed to switch Amy & Catherine back in Witch when he hadn't exposed himself to magick in years.
Magick may have always been a part of Willow internally without her even knowing it, but she did not treat it naturally, sacred, or like something that comes from within. She never seemed to look within. She sought out, grabbed hold of the external.
With Tara, you can see that she is a "natural witch." You feel that divinity within her. The power does not feel foreign, borrowed, or stolen. She seems one with it and knows it is not something that you master but something that you are and always have been. She seemed to have more respect for the natural order, the flow of things, and shaped her moral code out of her spiritual beliefs.
I agree that Willow needed someone like Jenny or Tara or the English coven from the beginning. Jenny was already gone when Willow started down her magickal journey and by the time she met another in-tune-with-nature-knows-everything-is-connected witch, it was too late. Willow was set in her ways. It's easier to teach and guide someone when they are a clean slate than when their mind is filled with false facts and ingrained dogmas.
I do not think you are attacking anyone's thoughts/opinions. I like that you can even hear someone disagree about Willow and list reasons why you feel differently. Whenever I say something about Cordelia people completely ignore it, get pissed, or accuse me of being a blind Bangel shipper (despite the fact that I also ship Spuffy).
