75 of my top 170 anime are derived from manga.
41 are original, ie, not derived from anything.
29 from light novels.
20 from visual novels.
And 7 from video games.
(Some shows have multiple sources which is why the number exceeds 170)
In other words, the lion's share of good anime comes from good manga. However, most good manga hasn't actually finished being published yet. This per force means most anime has no proper conclusion as well. The animators are as in the dark as to what the ending is as we are. The majority of manga-based anime are physically incapable of producing a sequel because there isn't enough content to support it yet.
For manga that does have enough content for an additional anime season, we come across a new problem. A manga which is neither introducing nor resolving any issue is far less interesting or worthwhile to animate than, say, the introduction of some altogether new series instead. This middle section of a story is basically boring. For instance, there's plenty of additional Kimi ni Todoke content in the manga, or Chihayafuru content, but what has actually happened after the anime of these series ended?
In Kimi ni Todoke's case, nothing of consequence has happened to anyone. Chizu and Ryu got together, but they were essentially together from the beginning so nothing has changed there. Ayane is dating yet another guy and yet again isn't serious about him, so nothing is new there either. Meanwhile, Sawako and Shouta are dating, just as the ending of the anime would have you expect, and there's been no change in their lives since then. So yes, technically, they could make a ton of new anime episodes of Kimi ni Todoke, but what's the point? The climax, Sawako and Shouta getting together, was animated. After that nothing of note has happened in the manga, even though chapter after chapter of meaningless content have piled on since then, like some blizzard in Siberia that never ends.
Likewise, in Chihayafuru, there's plenty more in the manga that hasn't been shown yet. But what, really, has happened since the anime ended? Chihaya recovers from surgery and wins her first tournament, with her opponent being of all people her fellow club member Taiki. After that, the meijin/queen finals for the year occur, but none of the main cast even qualify for the contests. That's it. Chihaya wins a tournament, and then skips the queen contest to go on a school field trip. Are you really going to make an anime about that? It's all so empty. It's like serving someone bowl after bowl of plain white rice and expecting them to scarf it all down. Anime episodes are expensive. If they lack any impact, any point to even existing, how can you justify the expense to your superiors? Why would you think fans would buy the expensive blu-ray disks that contain said episodes?
I don't think it's utterly valueless to have these scenes in Kimi ni Todoke or Chihayafuru. I just think that if you're going to have such boring content, it's a lot better to have it in manga form than anime form. Manga can be read much faster than anime can be watched, so even boring sections don't drag on too long in manga form. In addition, manga is much cheaper both to make and acquire, so for both the producer and the consumer a lower price allows the commercial transaction to occur which would have been prohibitive if it were in anime form.
Bastard is another example of a series that has plenty of new content, but none of it really adds up to much. Do you really want an entire anime season to be 'humanity vs. angels, the longest battle in history?' No character introductions, no important decisions, no characterization or development, essentially no dialogue at all -- just fight, fight, fight more and more angels, all of whom are saying the exact same thing, because it's all just one conflict from beginning to end. This is not animatable material. It's essentially meaningless. Fluff like this is fine so long as you can zoom through it and just admire the gorgeous artwork (of which there's plenty), but watching a 24 episode season of pure action scenes and repetitive dialogue that reads, "Die, human!" "No, we'll go on living!" for 50 hours straight? Which studio is going to think that this is a surefire seller? A hit in the making?
Some series manage to continuously reinvent themselves and create new interesting situations one after another. High School of the Dead, Btooom!, Shingeki no Kyojin, Railgun, Saki, Hayate no Gotoku, The World God Only Knows, and Sora no Otoshimono are good examples. They introduce new characters, have new heartrending scenes, put protagonists in situations they've never been in before, and keep the story fresh and dynamic, as though it were a lot of new series one after another instead of just telling the same story over and over again, or drawing out the same situation for endless boring stretches. Some shows do drag out for a long time, like Naruto or Bleach, but are so compelling in their execution that you wouldn't mind watching it anyway. When your level of excitement and interest in the story reaches a certain fever pitch, even one hundred episodes concerning the exact same fight can sound like heaven. The same can't be said of Prince of Tennis or Kenichi. Some series can keep even the middle of a show top notch -- most can't. Continuing an anime of manga series that don't know how to get to a point just won't work out for anyone. Certain stories can only be told in manga format, because readers are more forgiving of manga. Any attempt to animate such long drawn out content would just end up a money-sucking flop.
If you find a good manga with a great introduction, no ending in sight, and a long drawn out or repetitive middle, do you just not animate it at all? Or do you animate the first twelve episodes or so, when the setting, plot, and characters are all being introduced, and then switch the fanbase over to the manga where they will enjoy the product more from there on? It seems pretty reasonable to just end your anime on a high point and tell people to enjoy the long, boring portions from here on in black and white. This way viewers get the best of both worlds. The most exciting portion of the series done in the most exciting way, and the most boring portion of the series done in the easiest and cheapest way. The story gets told, and the fan attention can be preserved and cultivated despite the dip in quality.
I won't demand an anime sequel to every single manga-based anime until the anime is fully caught up with the manga. There are diminishing returns to most manga-based anime that kick in rather quickly. I'll simply demand an anime sequel to manga-based anime that I feel are still fresh and fun every time I see them -- like Mikakunin de Shinkoukei or Sakura Trick. Now these are shows that could still use a sequel, because I still haven't seen everything these wonderful authors have to offer yet -- I feel like the story is still changing and progressing right before my eyes, so I don't want to miss a single moment.
Meanwhile, I've updated my rankings to reflect the ongoing changes for the summer season. Aldnoah.Zero turns out to be much better than I initially thought. We have a solid cast of characters, a constantly whipsawing series of plot developments which nevertheless all seem consistent and believable, and unbelievably high production quality -- soundtrack, animation, art style, whatever you want to talk about. As such, Aldnoah.Zero gets to slip in as my seventh new addition to my top 170 rankings at the very last place. We'll see how far it rises from here, but 170th is already a fantastic achievement. My other summer shows have also all risen in the ranks based on their good performances so far. Glasslip is already up to 96th, and appears to be the standout new show of the season.
I dropped Sailor Moon back down to 51st in my rankings. This is because, looking back, the original 1990's show is virtually worthless in comparison to Crystal. The art is low detailed, and the characters look childish, completely different from how they're portrayed in the manga. The sound quality is poor, the resolution is obviously grim, the series is full of filler, and half of it is changed entirely from its original concept. With such a mangled production, it's just like Dragon Ball without its Kai remake. IE, unwatchably bad. Only the remake has any value as an anime at all. But that remake, which is extraordinarily good, only covers the first arc of Sailor Moon. There's no telling if it will cover the whole story. If it only covers the first arc, like the title 'Crystal' implies, then it will only be 1/5 as good as if it had covered the whole story. In fact, you could argue it's only 1/10 or 1/20 as good, since the 1st arc isn't even the one most famous for why Sailor Moon is such a good manga. Until the anime is guaranteed to continue until the whole manga is adapted, Sailor Moon can never be a great anime. Sailor Moon Crystal can, on its own, be a 'good' show, but it's nowhere near the level of a top 10 entry. Sailor Moon and Dragon Ball seem to be suffering from the same curse of 'a good show that was made into a bad anime too early, when anime budgets and technology simply weren't high enough to produce good art.' The curse of being made before 2000 really is striking. It's almost unrecoverable. It appears only Ranma 1/2 can survive without a remake, after all is said and done.
Meanwhile, I moved Majikoi up to 77th. This is because the show is much better than I previously remember it being, upon rewatching. I think I was more moved rewatching the show than I was the first time, which is a pretty remarkable feat. What do I like about this show? Let me count the ways. Obviously, A, the girls are beautiful, as expected of a nudity-fest based on a top selling eroge of the year. However, the not so obvious benefits are the ones that rise it above competition like Queen's Blade. The fact that the villains were fighting as hard or harder than the heroes, they were so desperate for victory, is pressed clearly into the psyche. Nor were they fighting for themselves, but instead they were both ready to sacrifice their lives in order to simply communicate their message to the country and try to change the people's mood for the better. In the end, the villains were the heroes, and in the end the villains won, which was the happiest ending possible. That's a great change of pace from any ordinary tale. The third thing I love so much about this show is when all the girls challenged Moyomo to a duel for Yamato's love, because they wouldn't put up with her monopolizing his time and heart while not even loving him back as a woman. Their passionate speech that men have needs and even Yamato has the right to be loved back in turn by a woman, no matter how self-effacing he is and how willing he is to bend over backwards for his crush, was really wonderful. I love when women stand up for men, or men for women, because it shows that they aren't just self-interested egotists who center their morality around what they can get for themselves. The fact that Wanko refused to go down in her fight against Momoyo, even though she was totally outclassed, because she would rather die than give up on the love of her life, really strikes to the heart. Really, all the girls in this series are so wonderful, because they all carry such strong convictions in their hearts. Majikoi is a really suitable title for such a show. It doesn't hurt that the art/animation/choreography of the fight scenes are fantastic.
Unlike Aldnoah.Zero, Rokujouma no Shinryakusha dropped dramatically in quality, which was somewhat expected. The haphazard plot couldn't come together, and ends up just being a mess. A bunch of people hang out together who ordinarily would have nothing to do with each other by blind chance. Am I supposed to believe such a group will really become friends? I don't see that happening. If it does happen, I'll resent the show for being unbelievable. (Friends are scientifically proven to be as related as 4th cousins, married couples have the same education/intelligence levels, etc. Only like attracts like. This is an indisputable law of nature.) If it doesn't happen, I'll resent the show for being too acrimonious. I hate series where the cast doesn't get along with each other. It just makes me feel like I'm stuck in a room full of yelling, angry, violent adults and have to curl up into a corner and cry myself to sleep. Give me K-On levels of affection or give me death. So Rokujouma no longer has any way to satisfy me. I'll be unhappy with anything it does anymore. The art is still good and the humor is still funny, so I'll hang on for now, but this show will never rise to the level of masterpiece like Aldnoah.Zero managed to do.
With more information accrued, here's how my 'eagerly anticipated summer shows' ranking looks now:
1. Sailor Moon Crystal
2. Sword Art Online II
3. Fate/Kaleid Liner Prisma Illya 2wei
4. Fairy Tail
7. Ao Haru Ride
11. One Piece
12. Dragonball Kai Buu
13. Yama no Susume: Second Season
14. Gekkan Shoujo Nozaki-kun
15. Hunter x Hunter
16. Happiness Charge Precure
17. Jojo's Bizarre Adventure: Stardust Crusaders
18. Tokyo ESP
19. Akame ga Kill
20. Rokujouma no Shinryakusha?!