I don't believe any of the problems the plot sets off at the beginning of the album is resolved and I don't believe justice was done.
How exactly are the problems not solved? In the beginning we have no humanmade music and a huge wealth gap between the rich and poor.
In the end, the emperor powers down the NOMACS and allows human music back into the world. Additionally, "we will build a world on common ground/people we will never hold you down" as well as Faythe's "I will be a voice for change so they can live the life they never had" is a promise from the rich to close that gap. I don't know how they'll go about doing it, but I'd say that's a very optimistic start.
Additionally, as a result of this, Xander gets the better life that Arhys promised Evangeline.
Also, in terms of Justice, the most evil character Daryus was punished by becoming permanently deaf in a world that will soon be filled with astonishing humanmade music.
First of all I don't think the music deal was the only problem that Arhys and the rebels had, I don't even think it was on their top 3 problems.
A "cold blooded, wicked tyrant" who's reign is distinguished by "corruption and greed", people are in rags and "live the life of misery and pain", overworked like slaves as we see in the trailer, have constant surveillance from the NOMAC's and "we will build a world on common ground/people we will never hold you down" is the explanation to how all this was resolved and justice is done?
The man who killed the leader of the rebellion, orphaned his child and threatened to kill that child twice, is going to be the next emperor and there is no proof on the album of that not happening, am I to think that Gabriel is going to tell the Ravenskill militia "it's all good now, we have human music" and they'll quit fighting after their leader has been murdered by heir of the emperor they were rebelling against?
Are we to assume that a child who witnessed his father's death is not traumatized? let alone accept growing up with Daryus going unpunished? Tell a kid who sees his father's murderer walk free that it's okay cause he's deaf..
I can accept all this if the story should be treated like a fairy tale where these details shouldn't matter.
Like I said, "we will build a world..." isn't the end, but it's the beginning of the answer. Of course it'll take time to go from rags to better, and that could take years to get done, but there's definitely a process starting.
The cold-blooded wickedness probably came from the incessant drone of the NOMACS. Someone mentioned either here or another thread that the NOMACS have clouded Nafaryus's judgment. The end of the NOMACS as well as the "pride and ignorance [receding] to reveal a humbled man" will most likely end that wickedness.
Daryus, I'll admit, him being the next emperor seems like a problem that can't just be pushed aside because he's deaf. But if we're going back to the whole "building a world on common ground" idea, it's quite probable they'll go back to a Democratic Republic like it was 300 years ago. A House of Representatives where everyone gets a voice. Elected leaders rather than feudalism.
Of course X will carry that trauma forever, but he'll have Gabriel and Faythe to support him through it, unlike that kid in Looper who would've seen his mom die, escape on a train, and become the next Hitler.
The rebels were rebelling because they wanted a better life. Since the emperor is starting to promise that, there's no reason to rebel anymore.