For what anime movies with the "movie-only character" plotlines have become rather predictable time and time again, from the Ao no Exorcist Movie to Bleach: Memories of Nobody, however this movie is an exception.
For what with the huge new cast of characters in the movie LA was worried it might turn into the "movie-only character" plotline, but thankfully it did not as this movie really is a sequel to the TV series.
The new cast of characters are by in large villains to Gunzou and Iona and are in the form of "student council member" ships of Hiei voiced by M.A.O, Myoukou voiced by Ayaka Fukuhara, Nachi voiced by Satomi Sato, Haguro voiced by Hiromi Igarashi, Ashigara voiced by Suzuko Mimori and Musashi voiced by Rie Kugimiya as well as Yamato voiced by Mai Nakahara. LA would admit that almost half of the characters hardly get any development beside their abilities and personality and are more or less "heavy mooks" and the only three ships that get the focus are Musashi, Yamato and Hiei, Hiei about her conflicted relationship with Kongou and with Yamato and Musashi being the ship that drives this entire movie along. LA's favourite villain from Cadenza would be either Musashi because Rie Kugimiya or Ashigara because of her eccentric literally bombastic personality.
As for the main cast, well besides some banter to I-401's crew, they don't get much development and the sole proper focus goes to Gunzou and Iona with Takao, Hyuga, Haruna, Kirishima and Makie being support characters to help the main cast when they are needed. However once again Takao for LA took the limelight and was LA's favourite character in this movie (and might as well the TV series).
In terms of animation, done once again by SANZIGEN utilizing their "expertise" in 3D CGI, however LA can give the CGI some grace as EVERYTHING is CGI including the human and Mental Models, now you'd think LA would be irritated that, but since everything is CGI it blended together and really LA wouldn't bitch about the animation as the grand battle set pieces (to some extent the batshit crazy naval battles) were outstanding in terms of animation thus the animation for LA gets HUGE praise.
In terms of voice acting, for what the cast has expanded to, Rie Kugimiya as the main villain of this anime was great (as Rie Kugimiya has now a habit of voicing some unstable villains), while on the other side Suzuko Mimori voicing the eccentric Ashigara was great making the battles even more "batshit".
Now this movie does make changes to the character designs from the TV series, those being Hyuga, Makie and Kongou and LA at first didn't know why the re-designs but LA warmed up to them especially Hyuga's.
The plot twists within this movie does come in the form of "character coming to save the main cast" however those plot twists are more or less glorified and badass cameos for the battle set pieces, but the plot twists that concerns Iona, Gunzou and Musashi give more of a character evolution to them as well as bringing the plot full circle (from both this movie and the anime series).
The ending by all means DOES end this series but it's bittersweet with a great battle set piece to boot. It did close if not most of the plotlines while utilizing it's newer cast members and lore of the anime series making this ending satisfying though bittersweet at the same time.
If Aoki Hagane no Arpeggio: Ars Nova Cadenza does anything right is make the "movie-only" character plotline in anime movies make these "movie only" characters have a purpose and don't just "disappear to be forgotten" to the overall plotline to the anime's timeline. Seriously if you wanted closure in the Aoki Hagane no Arpeggio: Ars Nova series then Cadenza will deliver.
