Because for the first time, SAO became action-centric, rather than plot- or character-centric.
The TV anime focused heavily on its characters. The climax of the Aincrad arc was not Kirito beating the game (spoilers, I guess), but his last scene with Asuna. The Fairy Dance arc focused on its plot, and the Phantom Bullet and Mother's Rosario arcs were basically character studies. Since these things were written poorly, these arcs were poor as a result.
By the time Alicization came around, Kawahara learned how to write a good plot, and SAO Progressive marked his transition into writing good characters. It's an absolute joy to read about Kirito and Eugeo's exploits in Underworld, compared to the tedium of his harem in Aincrad.
By comparison, Ordinal Scale's plot is extremely simple and straightforward, largely serving as an excuse to serve up action scenes. It centers around a consumer-grade AR device called the Augma, presumably a precursor to Accel World's Neurolinkers (in more ways than one, as is eventually revealed). The conflict in the plot comes from the titular Ordinal Scale, an ARMMO for it. Think "Pokemon Go meets Aincrad," and you're in the right ballpark. Trouble befalls SAO survivors who die in Ordinal Scale, and it's up to Kirito to figure out what's happening and put a stop to it.
The villains are simple, cliche, and boring - you've seen them a million times before. Likewise, the new poster girl, Yuna, joins Yui, Eugeo, and Kizmel in Kawahara's growing list of "might as well just be human" AIs. The plot unfolds at a satisfying pace, utilizing a Mother's Rosario-esque structure. The story is completely self-contained. Basically, this is just another original anime movie for a popular anime. So why am I not giving this a five?
Because A-1 Pictures brought their A game on this one.
The action scenes are GORGEOUS. They're beautifully choreographed, making them easy to follow while simultaneously being fast and exciting. Even the final one, which was so fast-paced it'd put Sonic to shame, was an avalanche of awesomeness that I could enjoy without being confused. Captain America Civil War could've learned a thing or two from this movie.
Additionally, all the action scenes were backed by a frankly kickass soundtrack, noticeably getting me more excited than I would be without them. Say what you will about SAO, but you can't deny that it's always had amazing sound direction, and it really shows in this movie.
Don't get me wrong, though. There are plot holes. A LOT of them. How are these places in Tokyo empty enough for a bunch of LARPers to do their thing every night? Lemme tell you, I ain't ever seen the UDX plaza that empty, no matter how late it gets. How is the Augma not constantly making the news when people inevitably become spontaneously idiotic? Remember Pokemon Go? The Augma is supposedly even more prolific, and since it's a product, it's presumably here to stay. How are these make-believe battles actually making people recoil, making them encounter physical resistance to their movements (i.e. when they block an attack), sending them flying, and all these other things? How is Kirito - weak as he is in these battles - able to do even what he DOES accomplish? He is canonically a frail, weak, and slightly effeminate-looking nerd. In any other SAO production, I would not be able to forgive so many plot holes, which reek of the Kawahara who brought us the content of the TV anime. However, I can make an exception for Ordinal Scale.
The movie does not take itself seriously.
One problem with the TV anime is that it overblew the drama, making every single plot point feel like the end of the world. Ordinal Scale doesn't do that. It doesn't linger for longer than it should on any plot event, instead prioritizing constant movement to get to the next action scene. At one point, it even throws all logic and common sense right out the window, since it'd rather be awesome than have a coherent plot. The TV anime wanted you to take its stories and characters seriously, and that didn't work, since the writing was usually bad. By contrast, Ordinal Scale's writing is generally unremarkable (besides the litany of plot holes that perforate it like Swiss cheese), but it doesn't care. Rather than boast and brag and say, "Look at how great my story is," it instead directs your attention to the flashy and exciting fights. It just wants you to have a good time. Don't get me wrong - the fights were the best part of the TV anime too, but the difference is that Ordinal Scale WANTS you to focus on them. It succeeds at what it goes for, whereas the TV anime failed at what it was going for.
That said, there was no reason why there needed to be so many unexplained plot holes - even a comment in passing would have sufficed - so my final rating for Sword Art Online Movie: Ordinal Scale is a seven out of ten.
For all its flaws, it's hard to hate this movie, even for someone who's usually unimpressed by the SAO series. Existing fans will love it, and even haters might find something to like, too.
Also, what was up with that post-credits scene? Unless it spoiled the mastermind of the Alicization arc (which I haven't finished) or the Moon Cradle arc (which I haven't even started), then are we getting more anime-original content?
