She still killed a whole ton of people, and is responsible for most of the Dead Ends in F/SN by killing Shirou, who she is supposedly in creepy-Yandere-love with. She can't fight on her own (The only one out of the three heroines), she never helps Shirou, and she never shows her love for him in anything more than smiling at him, voracious unrelenting sex (Which, in Sakura's case, is too creepy to be a good thing, and is more for her than for Shirou), and killing him slightly more slowly or delayed than everyone else. She's not as cute as Tohsaka or Saber (IMO), in either appearance or mannerisms, she's boring as hell when she isn't being fucking crazy-evil, and she's still a passive aggressive bitch even without the ultimate evil that's apparently making its home in her belly.
She ruined Heaven's Feel for me. She wasn't worth all the effort Shirou went through for her (More than the effort for Saber or Tohsaka, who are both far more worth it). In fact, while Fate revolved around Saber and her Self-Doubt, and UBW revolved around Archer/Shirou, Heaven's Feel did not revolve around Sakura as much as it revolved around Shirou sacrificing things for her. Shirou is driven by an urge to protect and soothe this girl who constantly lashes out at him whenever he tries to do so, whether openly, passive-aggressively, or through her super-death-shadow-monster. What should have been an epic end to the VN was stained by the constant realization that I traded Saber, and, to a lesser extent, Tohsaka (merely by amount of focus) for Sakura, and that is not a fair trade. I would have much rather the game ended after UBW, because Heaven's Feel left a nasty taste in my mouth simply for her involvement in it.
Thus, not only does the character herself reek of Bitchery and Crazy, with no redeeming qualities aside from Physical attractiveness (And if you've looked at Saber or Tohsaka, that doesn't mean much), and absolutely nothing interesting to say that isn't a vapid, desolate vacuum of hollow Moe attempts, but the very existence of her in the story ruined the last 35-45% of it for me. Even watching the True End of Heaven's Feel actually left me pissed off, simply because Sakura got an ending with Shirou, and Saber (who really, really deserved one where she didn't have to share him with Tohsaka) did not.
You can fault Shinji for a lot of that, simply by his constant rapeage and general dickery, but I can't help but feel that at the heart of this purple-haired girl, without any Shinji, or Zouken, lies that same Passive-Agressive, Jealous, Vindictive, Spiteful Bitch that she is in Heaven's Feel. She'd probably be a lot less crazy, a lot less murderous, and a lot less Nymphomaniacal, but she would still be a Bitch, undeserving of Shirou's unwavering, self-sacrificing, and misplaced love.