It's kind of weird because as much as I hate the death of some characters, namely Jenny and Tara, I feel like every death was so important to the storyline or meant so much, and many offered extremely powerful scenes, heck even funny scenes (Snyder). So I'm not even sure if I would want to take any deaths back. Many of those deaths are also counted as some of my favourite scenes or episode in the series. Just a few examples;
The Body - one of the most powerful episode I have ever seen, and I don't think I have ever connected with a moment on TV like that ever before.
Passion - gruesome, hurtful, beautiful, torturous, this death had so many emotions, I don't think I'd want to take away this episode, which is in my top 5 eps of BtVS
Tara's death - pure surprise, and I mean like shock that didn't leave for 2 weeks. A TV show had never surprised me like that before, and I don't think it ever will again. Plus we get DW, my favourite bad guy in the verse
But if I had to choose, it'd be a toss up between two characters, Tara and Giles. Tara I would actually had preferred if they brought her back after her death, so technically I still want the death, I just don't want her to stay dead. Giles, well scrapped that whole death because killing Giles is like killing the franchise, you cannot touch one of the core Scoobie. Just don't. Bad Joss.