The blurb on the back of the case is definately a hyperbole, but it's marketing speak. It's still a surberbly told story about two people who care about each other, regardless of the time/distance between them.
The main emotion being shown in Voices is longing. It's a pretty tough emotion to portray, since it's usually everpresent and internal. It's subtle, but their time together in the beginning shows they care about each other by how relaxed they are around each other. Just by the way Noboru constantly checks his messages shows they he's always thinking about her. Even after the first jump, when he decides it's time to stop waiting, when he finally recieves mail from her, he's obviously distraught and you can tell the feelings are still there. He has to vow to himself move on, but can't. Even at 24, he's waited all that time because no matter what, he still can't forget her. He's still keeping up with the armada, he's looking into the latest communications technology. He may have moved on, it's implied he decided not to but we can't tell, but this is still a big part of his life, to the point where he's joined the next armada. It builds slowly to the climax, where they reaffirm if there is one thing they could say to each other, it's that they were still there.
I honestly think overt emotions the likes what we usually see in anime would have ruined the piece. In fact, I think it's demure, subtle way of storytelling only enhances the quality.If you want to talk pretension, you usually point to Makoto Shinkai's other works, not Voices. Voices is very simply told, but thats what makes it good.
Maybe it spoke to me because I've been in long distance relationships and I know the feelings that the characters are going through, but I think that would make me more critical of it if they got it wrong.
The anime also gets props for using the Gunbuster style cockpit. >.>