>>188931257>Saber's bound to her Master, Sakura's mostly just a damsel in distress, but Rin's got her own staying power and agenda and, at least somewhat, is her own factor in the story separate from Shirou.
You might be correct in that Saber is kinda stuck on Shirou, but Sakura was in actual distress, that was why she didn't just burst out with hotblooded action like her sister who was if you'll remember, properly trained in the art her body was born to use, not abused, and praised for her accomplishments. If course she looks like the more well to do one. However, Sakura rose up once freed and has a very multi faceted lifestyle that isn't just about magecraft. Not meaning to offend, but Rin is very much a career magus and kinda shirks her other relationships outside of dating and possibly marrying Shirou, I would doubt she and Ayako would talk at all after they graduate. While Sakura not only becomes captain of her archery club, taking them to nationals before passing the torch, but gets into botany and might become an arborist on the side. In addition, she has a bishop of the church who she not only found to train her, he's essentially a father figure to her, and she found that mentor on her own, when she has every right to forsake magecraft forever through her experiences.
Of the two stories, I would say you can make more meaty speculative stories with Sakura.