The greatest tragedy of Tara’s death wasn’t that she was murdered. It wasn’t that she was killed by a man who was trying to kill her friend. It wasn’t that she was young, or that she was beautiful, or that she had so much more life to live. The greatest tragedy of Tara’s death was that she had only just reconciled with Willow.
Tara was the purest of all the characters on Buffy. She was kind and gentle and sweet, and in the end she was the only one who was never seduced by evil. Maybe that, more than anything else, meant she had to die. Maybe the inhabitants of Sunnydale can only live on the Hellmouth for so long until it takes over them completely. Maybe if Tara hadn’t been accidentally murdered by an evil man with a heart full of hate she would have turned evil, like Angel, like Buffy, like Willow herself.
Or maybe if Tara had lived she would have stayed pure, and kept Willow pure alongside her. Maybe if Tara had lived they would have saved the world, and moved to Scotland and raised magic sheep in the Highlands. Maybe they would have explored the world, the universe, the dimensions beyond, and return to Buffy when she needed them. Maybe they would have grown old together (always together), and raised cats like Miss Kitty Fantastico. Maybe they would become old witches, living together in a decrepit mansion on a small island where the neighborhood children wouldn’t be able to decide whether they’re afraid of the old witches or in awe of them (or perhaps a little bit of both).
And then, after they had saved the world more than anyone has ever saved the world (except perhaps Buffy), they would lie down together and depart for the next great adventure. And Tara would still have died in Willow’s arms, and she would still have died knowing what it was like to be loved, but it would be a kinder death, a gentler death, a sweeter death. A death to fit Tara herself.