It is explained dude. There's like five whole eps of material where ninja powers are explained with the elemental affinity people are born with and in connection to that they have the potential to learn several different techniques. I'm sure you remember them. It's not that much either and it doesn't always make too much sense, but it fits in the world concept and isn't total bullshit for the most part. Also on top of that, the people who can use a teleport like technique in Naruto are the fucking strongest guys on the planet (which makes totally fucking sense), where as in Bleach, every character with a powerlevel above 100 can do Shunpos and Sonidos like crazy and it doesn't mean shit, because the battles in Bleach make no fucking sense. Next to no character in Bleach actually wants to win if they cannot totally crush their opponent in any possible way and yeeaaahh, they do take the risk of losing their lifes if it means that there will be options to talk them until they're deaf. Wars actually are wars in Naruto and not some talk show rumble farce with Aizen as the Oprah Winfrey.
Naruto compared to that has (excluding fillers of course) well thought out battles for the most part, at least compared to Bleach.
Don't get me wrong though, you're right about there not being much more when it comes to logic in other shounen anime either. I'm just saying that they're not utter garbage with a plot hole every two steps they take.
You're saying that, but he's still 5000% compared to Aizen. Sephiroth is strong, because he's a (non-failed) mutant made by the science studios of a monopolizing company (and there's alot known about them) through combining Jenova cells in the womb of a female human. And then there's the story about him finding out what that company did to him and decides to change sides.Aizen got his technique cause he's a fucking ghost, and ghosts have magic powers and his powers are stronger cause he's the main villain.
And I can't believe you used fucking Sephiroth as your go-to example for a "well thought out villain". He's Mary Sue incarnate.
It's not too much, but it makes sense in the world they're living in. There's psychological conflicts and interesting plot turnarounds. It's a whole network where every cogwheel has it's place. It's enough. Resident Evil doesn't offer more either and it made it to international cinemas. And there's also other (failed) subjects who are still strong, but not as strong as him and all of them (including Sephiroth later on) suffer from side effects. It's a well thought out gain/loss concept.
Aizen has... nothing. And nobody knows anything about him, neither is it ever explained how differences in shinigami powers are even accomplished in their nature. Natural selection? Possible. But if there's that great of a "gamebreaking" difference, it has to be explained or it throws the world concept overboard. When talking about Bleach, there's always assuming and barely ever any facts which explain essential logical indications.
"Aizen is just a super genius in any possible way (why and how? nobody knows) who does inhuman experiments to gain results and accomplish "higher greatness" and "a new world". That's all." Live with it or get the fuck outta here. Now that's one of the worst possible ways to treat a fanbase. You can't do that. It just has no credibility. If someone invents a light bulb you can say he was able to do that due to natural selection and because he has an outstanding IQ (like 30 above the average) and on top of that was lucky. But you can't make someone a super genius in anything possible without explaining how he got to it. That's just not okay.
Isn't that like the first thing Urahara, the professor Captain or any scientist should wonder about before they get into anything else?