Bleach's Ichigo Kurosaki was a bit outlier among the protagonists of Shonen Jump's "Big 3" (One Piece, Naruto and Bleach). When these titles were still all serialized together, certain trends were finally being cemented that would become staples of shonen storytelling. One such staple was giving the hero a distinct, fantastic world to journey through. For One Piece it was the high seas of the Grand Line and for Naruto, the many hidden villages of the ninja world. Bleach was a bit different because, although it had ghosts and Soul Reapers, it still took place in the real world, meaning Ichigo was more like a real person. It is this realness that managed to make Ichigo stand out among the other shonen heroes.
Ichigo went to school every day, he had friends he liked to hang out with, he took care of his sisters. By comparison, Ichigo is a much more grounded character compared to the likes of Luffy or Naruto. In fact, early in Bleach's run, Kubo makes a point of mentioning Ichigo's high test scores, marking him as a pretty good student, or at the very least an attentive one. It's a minor detail one wouldn't expect out of shonen protagonist.
Even his tragic backstory is also a bit more grounded, as Ichigo lost his mother when he was young and blamed himself for it. This tragedy is a deep part of his character, in how he's so protective of his friends and family, and especially respectful to the ghosts he sees in his daily life. The series opens with Ichigo forcing a bunch of delinquents to apologize to the ghost of a girl after they knocked over her memorial flowers. Despite the borderline delinquent attitude, Ichigo is stand up guy and mature for his age, fitting for a teen saddled with so much family responsibility. Even the very presence of this family makes Ichigo different, separating him from the orphans and wayward sons of the genre. Ichigo Kurosaki, aside from his ability to see ghosts, feels like a real guy dealing with real problems. He's an individual, but he's not "The Special," nothing marks him as being especially above any one of his peers — which, in this case, is a nice change of pace.
Ichigo also had to actually work to develop the powers he had. Although he had unusually high spiritual pressure thanks to his Soul Reaper father and Quincy mother, Ichigo was otherwise an average Joe with little in the way of latent power. It took Rukia making him a substitute Soul Reaper for anything to get rolling for Ichigo. Unlike Naruto, Ichigo didn't have any initial training, which meant once he did start training, he had to work much harder to catch up. During the Soul Society Arc, Ichigo had to achieve the Bankai state in just a few days, a form that normally takes true Soul Reapers decades to master. It might feel contrived to some that Ichigo can keep up with these Reapers and Arrancar who have walked the earth for centuries, but Ichigo's training comes with a substantial amount of risk to himself and bitter work. But, he put in the time and reaped the rewards, like anyone with the resources would.
Despite being a Big Shonen Hero, with graduation approaching during the Fullbringer Arc even Ichigo finds himself unsure of his future. What's interesting about this is that's such a stark contrast from Luffy and Naruto. Even non-fans of the series could tell you what the two MCs' motivations are: Become the King of the Pirates and become the Hokage. However, Ichigo doesn't have that kind of long term goal in mind. He's got no idea what he wants to do, which is something a lot of high school students could likely felt by the time they reached this part of Bleach.
Although Kubo's storytelling is a bit clumsy in the later arcs, his ability to make interesting, likable characters has never to come into question. Ichigo isn't a hero on the path to do good, he's a teenager who just wants his friends and family close by and he'll go the gates of hell (or in this case, the Soul Society and Hueco Mundo) to bring them back.