The original Bleach manga and anime did a fantastic job of depicting the personal growth of all its best heroes, including protagonist Ichigo Kurosaki, who went from a directionless kid with unprocessed grief to a noble hero who can save the world. The same was also true for Ichigo's friends, such as his lover Orihime Inoue and his rival turned friend, Uryu Ishida. Meanwhile, the Soul Reaper Rukia Kuchiki also had the same growth, but it didn't feel the same.
Source：https://www.cbr.com/why-bleach-needs-a-rukia-kuchiki-spin-off/
