There is a large pool of Bleach characters with mindblowing capabilities who appear to have an uncapped power potential, which is part of why this shonen is so captivating in the first place! Unfortunately, Tite Kubo only has so much time to work with and could not possibly give everyone the credit they deserve, resulting in some individuals falling through the cracks before reaching their peak.
In this male-dominated action-packed supernatural story, it seems that more girls are sitting on the sidelines (even though they clearly have what it takes to hold their own on the battlefield). Most of the time, nerfing certain characters helps to cast their significant others in a better light and, as everybody knows, too many cooks spoil the broth.
This article will contain spoilers from Bleach: Thousand Year Blood War, currently streaming on Hulu.
9 Ruining Rukia's Reputation
Even though Rukia Kuchiki plays a crucial role in the Bleach storyline and is essentially the main reason Ichigo becomes a Substitute Shinigami and is introduced to the Gotei 13 in the first place, she often falls too close to the realm of the manic pixie dream girl and isn't given the credit she is due.
Rukia has to appear weak in the Agent of the Shinigami Arc to set up the storyline, as an inexperienced Ichigo would not have left the same impression alongside an overpowered and accomplished ally. However, as the narrative progresses, this Shinigami's significance during combat never really improves, even after she achieves her phenomenal freezing Bankai, Hakka no Togame. Rukia is essentially a one-hit-wonder who is all talk and no action.
8 Misappropriating Mashiro
Ichigo is not the only Shinigami capable of tapping into his Hollow potential, as there is a whole group of Visored warriors in Bleach that made quite a significant contribution to Aizen's downfall (and are due to make another jaw-dropping appearance in the Thousand Year Blood War). While most of the Visored aren't granted the opportunity to live up to their full potential, Mashiro arguably gets the worst treatment even though she can maintain her Hollofication form for the longest (an impressive fifteen hours!)
Mashiro is depicted as being highly immature and exasperating while still being lethal enough to dominate on the battlefield without even using her Zanpakuto. Unfortunately, her role as comic relief is apparently more important than her deep connection to her inner Hollow. Ichigo receives a drastic difference in power level once his bond with Zangetsu is solidified, whereas Mashiro does not receive the same benefits.
7 Sidelining Sasakibe
Sasakibe Chojiro was hand-selected by the Captain Commander himself to be the 1st Division's Lieutenant and Yamamoto's right-hand man, and considering his incredible Bankai, the choice seems to be a no-brainer. Yet fans rarely get to see Kōkō Gonryō Rikyū in all its glory, even when the end of the world seems imminent.
Gonryōmaru's special ability allows Sasakibe to invoke the elemental powers of lighting and create a broad electrical storm around himself which can subsequently be directed toward his enemies. Essentially, Sasakibe could take out an entire troupe of foes singlehandedly, however, he wouldn't want to outshine his master (or scar him again) by unleashing his remarkable powers.
6 Unohana's Undercover Abilities
The Captain of the 4th Division sends out strong support character vibes, particularly because she is responsible for the health and safety of her allies (and sometimes, her enemies, too.) Little do anime viewers know, but Retsu Unohana is one of the deadliest (and ruthless) Shinigami around, who has rightfully earned the Kenpachi title, awarded exclusively to one individual in each generation who has executed the most enemies.
While Minazuki's Shikai conforms to expectations with its healing properties, its Bankai has the reverse effect and showers Unohana's victims in an erosive, acidic blood-red sludge instead. The former sadistic miscreant opted to bury this potent power many years ago when combat ceased to excite her (at least, until a worthy opponent is found).
5 Ryuken The Representative
If the Thousand Year Blood War has proven anything, it's how incredibly powerful the Quincy are, and, even though Ryuken Ishida is technically just a doctor now, he did very little to represent his people's potency and spends more time degrading them instead.
For the most part, Uryu (and to a degree, his grandfather, Sōken) is the sole link that viewers have to the Quincy, while Ryuken only pops in every now and again to antagonize his son more than anything. He will happily hold Quincy Encyclopedia sessions with the audience and yet reprimand Uryu for wanting to learn more about his Clan while finding more satisfaction in healing the living than saving (dead) souls. Maybe the persuasive Yhwach will help Ryuken change his tune.
4 Shunning Tatsuki
There is certainly a fair share of humans involved in the supernatural conflict of Bleach and yet, for some reason, Tatsuki Arisawa just didn't make the cut. While she may not have magical hairclips, a fancy fullbringer, or a distinguished bloodline, Ichigo's childhood friend has shown great potential in hand-to-hand combat and has actually trained in martial arts for most of her life.
Besides her battle skills, Tatsuki has shown a keen perceptiveness to the spiritual realm and can sense when danger is near, even pinpointing a Hollow's location (although she cannot actually see it). This bright-eyed youngster is intelligent, protective, witty, and hardcore, and would have made a great addition to Ichigo's little team of heroes.
3 Omitting Orihime
Orihime Inoue arguably has some of the greatest potential in Bleach, as the potency of Shun Shun Rikka directly correlates to her emotional state, it's just a shame she is such a timid and reserved girl! As the damsel-in-distress of the series, the entire Arrancar Arc would have been rendered obsolete if Orihime could have escaped by herself, but the Stockholm syndrome coupled with her nerfed abilities wouldn't allow for such a plot twist.
The fact that Aizen targets Orihime in the first place, or that the Gotei 13 seem terribly worried about this undesired coupling, is a testament to Shun Shun Rikka's strength (especially if used in more aggressively driven hands). Orihime offers great support for her allies, but there is so much more she could accomplish if given the chance to shine.
2 Nerfing Nanao
Captain Shunsui Kyōraku is certainly a big deal in Bleach, particularly after Yhwach arrives on the scene, so why does his most trusted lieutenant get so severely pigeonholed? Nanao is potentially the only Shinigami to possess a generational Zanpakuto that has a significant ritualistic purpose, which is subsequently left sheathed while she uses her impeccable Kidō skills instead.
Although there are many accomplished warriors who do not use their Zanpakuto to their full potential (Kenpachi, Matsumoto, Yoruichi, etc.) at least their characters have been adequately fleshed out to compensate, and yet Nanao barely gets enough screentime to speak, let alone fight. Her contribution to the Thousand Year Blood War will rectify things slightly, however, it may be too little, too late.
1 Tessai The Tease
There are but a handful of Shinigami who are not affiliated with the Gotei 13, however, most of these rogue warriors can cause some serious damage on the battlefield, regardless of their "insufficient" status. Tessai was exiled from Serieitei alongside Urahara and Yoruichi many moons ago but, unlike his closest companions, he appears to have lost many of his skills along the way.
Tessai may be a trivial shop assistant today but he once proudly held the Commander's position of the highly-esteemed Kidō Corps, making him the greatest Kidō master of his time. Sadly, even when Ichigo and his crew are training under Urahara's tutelage, fans don't get to see much of Tessai in action, which is a missed opportunity, to say the least.