I doubt you'll ever see this again. 2018 is so top-heavy. Virtually every high ranked series is receiving new content, while virtually no other series is getting anything.
I'm all for the best shows getting the most attention, that's only natural, but wow. Let's presume 39 episodes of new SAO, 26 new eps of Index, 50 new eps of Precure, One Piece, Bolt and Dragon Ball Super, 3 eps of Code Geass, 26 of Fairy Tail, 2 of Nanoha and 27 of Fate. That's 323 new episodes/movies of top 13 level content headed our way next year.
For everybody else? 26 eps of Full Metal Panic!, 6 eps of Girls und Panzer, 2 Hibike! movies, 26 eps of Macross, 26 eps of Shingeki no Kyojin, 12 of Koutetsujou no Kabaneri, 12 of Yama no Susume, and 12 of Card Captor Sakura. That's 122 eps. Let's assume six new series each of 12 eps in length also debut next year, just for argument's sake. 6 x 12 = 72 so that's still just 194 eps. The entire rest of the anime industry is going to produce less content than just the top 13 on their own next year. And it's not even close -- 3/5 to 2/5. 60/40.
Why is SAO the best anime ever? Because like 2-10, it's now adequately adapted, a necessary feature to compete for the top. It's also long enough to feature lots of interesting characters and handle convoluted, epic, detailed and involved plots and settings. There's plenty of time for character development and story arcs to feature all sorts of new and interesting ideas. These are all necessary features to be considered for the title of the best. Everyone in the top ten has these traits. This is generally what separates the top ten from everybody else.
11-15, for instance, aren't adequately adapted, so no matter how intrinsically good their stories are they stand no chance.
So SAO has the building blocks, the materials, the resources for success. But so do 2-10. What puts SAO ahead of the other nine titans at the top?
SAO has things the other shows don't. Death, and killing, are probably the most important features everybody else lacks. Only Clannad, Code Geass, and Fate have death in their series like SAO has, and only Code Geass has killing (ie, the main character kills someone, intentionally, with hatred in his heart, and no one gets on his case over it, because it was obviously the right thing to do and the target had it coming.). This lends an air of maturity and seriousness to the show that everybody else up here lacks. (Dragon Ball has death and killing, but death isn't permanent in their world so it's just a joke.)
Akame ga Kill! has death and killing, but it's ranked 179th instead of 1st because it wasn't adequately adapted. Worse, it was turned into filler halfway through and so the whole story is messed up beyond recognition. It's very difficult to get all the factors that make up a good anime in the same place, as the cautionary tale of Akame shows.
Does a good story require death and killing? No. Fairy Tail was my previous #1 and it has a strict no death/no killing policy. If you excel in other fields it's possible to get away with this deficit. But SAO has no particular weaknesses that might make up the difference, and Fairy Tail's weakness, its unrealistic fighting with no deaths and no killing can easily be outflanked by SAO's death/killing policy as a result.
The only question, then, is why SAO is better than Clannad (where there was no bad guy so it makes no sense to have killing, and there's plenty of death to go around) and Code Geass (which has lots of death and killing, enough to satisfy even the most bloodthirsty.)
SAO is better than Clannad because Kirito + Asuna are more my ideals of men and women, plus more my ideal couple, than Okizaki + Nagisa is. And I know what a statement that is. Okizaki and Nagisa are perfect and their relationship is perfect, so how on Earth do Kirito + Asuna surpass them? Because the two went through a Nietzchean ordeal that made them stronger than Okizaki or Nagisa could ever hope to become, and I admire strength of spirit/character more than practically any other trait in a person.
If Okizaki and Nagisa had been thrown into a death game for two years and forced to beat giant monsters and tricksty murderers and traitors in their midst while saving the world; falling in love with each other while learning more about themselves, then maybe they too could have evolved into the people Kirito and Asuna eventually became. But they didn't. That experience turned Kirito and Asuna into diamonds without parallel. They're literally the best people I've ever known. Asuna learning from Yuuki and standing up to her controlling mom just cemented that reality. Kirito's morality surpassing the taboo index's likewise.
So what about Code Geass? Why isn't Code Geass #1?
As much as I like Lelouch, there's something cleaner, purer, and better about Kirito. Lelouch is a guy haunted by demons who stared into the abyss for too long. He made a lot of mistakes and as a result is miserable and isolates himself from the rest of the world. In the end he could never accept anyone else into his heart, he couldn't even love himself. Kirito, who has a healthy sense of optimism and confidence and a great circle of friends and family, who has steadily devoted himself to a single girl for his entire life, who has pledged to marry the first girl he ever met, is the human ideal I strive for, not wannabe-druggee Lelouch.
And who is Code Geass's Asuna? C.C.? Shirley? Kahlen? Nunnaly? Euphemia? I don't even know. There are many important girls in Lelouch's life, but there is no single important girl to him, or the story. Suzaku probably trumps them all. I'm not into gay marriage so. . .
No but seriously, Asuna is closer to the female ideal than any of the females in Code Geass, and Kirito's relationship with Asuna is better than Lelouch's with any of his girls.
As exciting as a world war is and all the political shenanigans Lelouch deals with, I think Kirito's more personal adventures are more exciting and more relatable. Because the scale is small enough, it's possible for Kirito and Asuna to realistically make a difference in the world, in people's lives. In Code Geass they introduce the element of magic to make Lelouch's character have a significant enough influence on the world, but Kirito and Asuna are normal human beings. It's always better when you cleave closer to realism yet still achieve world-altering results.
Plus, swords and sorcery is better than mecha combat. Plus, the art style is better in SAO. Plus, SAO has a more varied and interesting setting than Code Geass. By moving between all these different virtual worlds with different rules, Kirito experiences several different lifetimes and realities, whereas Lelouch is restricted to just one.
There's a cumulative effect that slowly but surely tips the scales in SAO's favor across the board.
SAO also has marriage and child-rearing. Naruto, Dragon Ball and Clannad, among the other top ten, share this trait, but Code Geass very distinctly does not. I think family formation is extremely important to the human experience, so no story is complete without it.
The only show that has marriage and child rearing, death and killing is SAO. It's the only complete story on Earth, which is why it's #1. Other shows may have some of SAO's good traits, but none of them share all of the same good traits. SAO is the only complete package. SAO is the alpha and omega of storytelling, encompassing everything good about stories and compressing it into one packed dense singularity core. SAO is God.
Meanwhile, without even trying, I found another remix. Treasure, by Masaharu Iwata, occasionally just starts playing the same tune from Prologue Movie in the middle of an otherwise great, unique song. Sadly that's just not good enough. The whole song needs to be unique, not half of it, to not count as a remix. So away Treasure goes. The new total is 4320 songs, still 9.7 days in length.