Although I never hated or loved Kabuto, I am surprised by the lack of fans or even a strong hater base for him. I think he is one of the most interesting characters out there. Unlike most, he doesnt carry any "destiny" or "dreams" and most importantly, his character has never bothered us by soppy distracting flashbacks and all the time we have seen him, it has been in the most entertaining conflicts.
His major criticism is he is a wannabe Orochimaru, which I think is bull crap. Is utilizing what he has learned from someone strong and intelligent a drawback? Since SO6P gave birth to ninjutsu, are all ninjas wannabe rikudo? Even after Oro's death, whose motivations gave Kabuto a purpose in life, he picked himself up from a crony's status to becoming one of the key players in the fourth ninja war and he has still kept his real motivations a secret, which in my book deserves respect.
A.) You kind of pointed out some of the major issues with generating a fan base for him in your OP. I think what generates a fan base and haters, is having a character that is truly unique amongst the rest. For example, Deidara is one of my favorites. What's he known for principally his art. Is he alone in art? No. However, Kishi cleverly paired him with Sasori who had a directly opposing personality and view of what true art was. As well, Sasori only lasted a short while in the manga whereas Deidara lasted significantly longer in the manga and had a developed background and foreground. I'm not alone in being a fan as he was a top 10 in several weeks in Japan. That's not to say that I'm justifying my taste for him, but just to show that other people felt similarly. Further, he was very unique in his jutsu by using hands in hands and chests to mold special chakra clay to form explosive clay, that he molded into forms of artwork. Further, as Deidara would say, "Art is...a blast!" He had a philosophy that drove his ninjutsu, he didn't just blow crap up because that's what he was good at, it was because he thought it was art; otherwise, he could've just used a ball of clay to drop on someone instead of using little birds or centipedes for example. These things give a real dimension to the character and depth that allow the reader for better or worse to judge them and decide if this is someone who they will accept or reject based on whether they agree with this character's philosophy and personality. I personally accepted and enjoyed it, while others went the opposite way. Most importantly, no one else in the Narutoverse did things, nor has done things like Deidara except for perhaps Sai, but he has been developed such that his character is clearly distinct from Deidara despite his use of art for his ninjutsu since he's still learning what it means to be a person and not just a pure shinobi, as he was under Danzou in ANBU ROOT.
1.) Kabuto has no destiny or dreams according to your OP, the latter of which is incorrect, as we know he desires to know all the secrets of the Rikudou Sennin (that's why he's doing all this crap with Tobi, and stated as such a while back when he revealed that he had a "that jutsu" after revealing at least some of how Impure World Resurrection works). However, that desire isn't terribly original since several characters have desired that directly or indirectly including: Orochimaru (wanted to know all ninjutsu, clearly knows a ton about Rikudou Sennin as demonstrated by Kabuto's references to Orochimaru's knowledge), Tobi (essentially must want this to a degree in order to complete the Moon's Eye project, and has explained a great deal about the Rikudou Sennin to others such as Naruto and the Kage Summit), ET Madara (has mentioned Infinite Tsukiyomi, plans that Tobi is supposedly a part of or was, mentioned Nagato), Zetsu (kind of a mystery, but a confidant of Tobi in his plans and treated somewhat of an equal, kind of speculating to say more), and finally Sasuke may become involved in this as well as he seeks out more power as is his tendency. Thus, Kabutos desires don't really distinguish him from the other antagonists all that much except perhaps by his degree and focus of desire.
2.) Another point you made in your OP, there have been very limited flashbacks of Kabuto if I can recall any. Really, there's just been what Kabuto has recalled verbally about his past, which is really limited. Whereas the other major antagonists aside from Tobi and Zetsu who are intentionally being developed as mysteries (hence the masks with Tobi), and his intentionally misleading use of Madara's name for commanding respect and ease of manipulation, have been developed such as Sasuke and ET Madara the latter of which is continuously being developed as the fight with the 5 Kages continues as shown in the latest chapter. I would like to know more about Kabuto, it would help me care more about him. Give me a reason to care about him. How did he become Sasori's servant in Akatsuki for example? I would find that interesting. Why did he take his incredible skills in medical ninjutsu and turn them into the darker and more twisted nature, basically the opposite direction of Tsunade, given he was adopted and raised by the leader of the Konoha medical core? These are interesting questions that develop a character, at least in my opinion. :shrug:
3.) Kabuto has been involved in many major conflicts including the pre-time-skip, but until recently he hasn't been a central player until recently in any of them. In the invasion of Konoha all he did was cast the genjutsu really. In the battle of the Sannin, all he did was he get in toy battle with Tsunade who was about to kick his ass until he cut himself exploiting her fear of blood. Then he just served as a prop for Naruto to demonstrate his guts and perfect his Rasengan on. After the time-skip, when Naruto went 4 tails, at 3-tails he took Kabuto out of the fight with just a shout of chakra before anything happened between Naruto and Orochimaru, lol. Really, the 4th Great Ninja War has been his coming out party, and he's doing it by using a technique of Orochimaru's that he perfected, after he injected himself with Orochimaru's DNA making himself incredibly like Orochimaru. Further, his summons is just a genetically enhanced version of "Manda" called "Manda version 2", not terribly unique either. He couldn't come up with another name than tacking on "version 2?" lol
Come on the guy's a genius... How lazy is that...
4.) The criticism that he's a wannabe Orochimaru is legitimate because of not just that he wants to follow in his footsteps and learn the same techniques but because he looks so similar, and since he has acquired his DNA has seemingly replaced his own personality and goals to a degree with those of his former master. Before, did Kabuto have any interest in Sasuke? Before, did he have any interest in learning and mastering the Rikudou Senin's secrets and powers? These were Orochimaru's goals. Kabuto was a medical shinobi whose desire seemed to master everything in that field including the kinjutsu and beyond. Since injecting himself with Orochimaru's DNA, he's noted that there's been a struggle within himself for control, which took him a while to develop stability. However, I don't think he's the same person he was beforehand, simply with Orochimaru's abilities added on. I believe he's a different person as a consequence. Before, he also didn't do the Orochimaru, "kukuku" verbal laugh, now he does, why? Further, he doesn't just have Orochimaru's DNA, he also has been acquiring his chakra such as via Anko to strengthen himself and become closer to Orochimaru. Thus, again we reach the same issue that Kabuto is not necessarily distinguishing himself from the pack of antagonists of past and present. This is a critical issue for Kishi to address at some point. How he'll do so, I'm not sure; however, I do believe he will.
5.) Finally, Kabuto has never been outside of the servant's role in the manga. When he was with Sasori, Orochimaru, and now Tobi. Ironically, even when he's betraying Tobi by summoning ET Madara to the battlefield, he's acting in the servant's role to ET Madara despite the fact that he is the summoner. This is a turn off for many fans I believe. Always being number two, being behind someone, usually means that fans are rooting for whoever is number one (i.e. Orochimaru, Tobi, or ET Madara). At some point, and I believe that this relates to what I was saying at the end of the last paragraph, I believe Kabuto will be either be vanquished as a number two or the person in front of him will be eliminated allowing Kabuto to step forward and flourish as a primary antagonist. The question then is, will he become distinctive, or will he just continue to have these issues, which I've laid out in this post. Ultimately only Kishi will know the answer and be able to address these points as he writes the manga. Nonetheless, these are the reasons why I believe that Kabuto has not seen the fan base that you feel he deserves despite his demonstrated might as a ninja during the 4th Great Ninja War.
Peace
