One possible reason could be if she experiences a major loss, like losing a dear teammate in a very tragic way. This might shatter her confidence and make her question whether she's cut out for the dangerous life of a huntress.
In this fanfiction, Ruby could become a teacher. She would teach the next generation about the history of the huntsmen and huntresses, as well as the importance of unity and courage. By passing on her knowledge and values, she still plays an important role in the fight against the Grimm, just in a different way than being a huntress. She could inspire students to become great huntsmen and huntresses, and also share her combat experiences to help them in their training.
It would have a huge impact on her team. Weiss, Blake, and Yang would be devastated. They rely on Ruby's leadership and her unique skills. Without her, they might feel lost and less confident in their own abilities as a team.
One possible reason could be that she loses inspiration. Maybe she has explored all the ideas she initially had for her fanfiction and can't come up with new and exciting storylines. Another reason might be lack of time. If she gets involved in more important or urgent matters in the RWBY universe, she simply doesn't have the hours to sit down and write fanfiction anymore. Also, she could face criticism from others which makes her lose confidence in her writing and decide to give it up.
With Yang, their sisterly bond would still be strong but would manifest in different ways. Yang might be more protective in a non - huntress scenario, as Ruby would be less trained in combat. But at the same time, Ruby could offer Yang new perspectives on things outside of the huntress world. They could explore different career paths together, support each other's personal growth, and have a more domestic yet equally strong relationship, sharing their daily joys and sorrows without the constant threat of Grimm battles.
A really interesting plot could revolve around Ruby's relationships. Her Faunus family or friends might have different views on the ongoing conflict between Faunus and humans. Ruby, being raised in this environment, would be caught in the middle. She could try to bridge the gap between the two groups, leading to some intense and emotional story arcs as she tries to promote peace and understanding.
Another aspect could be the relationship between Ruby and the other characters. Since she's being raised by Ozpin, her interactions with Team RWBY might change. She could be more reserved or have different priorities. Maybe she'd be more involved in Ozpin's plans from the start, causing a rift between her and Weiss, Blake, or Yang who might not understand her sudden change in attitude.
One possible reason could be to explore different character dynamics. By changing their age order, fanfiction writers can create new storylines. For instance, it can lead to a different kind of sisterly bond between them.
One possible fanfiction could be about Ruby's journey as the Spring Maiden. She might struggle to control her new powers at first. For example, she could accidentally cause plants to grow uncontrollably during a battle, which both helps and hinders her team. As she learns to master her maiden powers, she could discover new ways to use them in combination with her scythe skills, making her an even more formidable fighter.
One possible fanfiction could be where Ruby is overprotective of her team during a dangerous mission. Maybe she constantly checks on their safety, making sure they don't take unnecessary risks. For example, when they are facing Grimm, she might be extra vigilant about any threats towards Weiss, Blake, and Yang, and jump in to protect them even before they realize the danger.
It could be that Ruby has to deal with the consequences of a major decision she made in the past. This causes her to question her leadership skills and she embarks on a journey of self - discovery to become a better leader for her team.