I do personally have the feeling that stuff that's considered flaws (i.e. the pretty dense and jarring structure and James' melodies) actually complement the theme. In my mind, of course a song about terraforming planets and exploring space in the context of Earth being wrecked is going to have an explorative, yet uneasy and uncertain tension about its progression and that also applies to the vocals that seem to rarely sit on a more singable melody other than the "Our holy grail..." and the "I am the alien..." bits, which feel like moments of acceptance (though not necessarily triumph) among the nervous chaos. For instance, the pretty jagged, hurried melody in the first verse concluding with "Options but a few, we are running out of time" feels very much appropriate. Same with how the part that ends in "...All that you've known left behind" has this kind of obscure, ominous vibe.
The tone keeps switching because in my opinion, a topic like this is pretty complicated and bittersweet (which the ending also musically seems to represent with that ecstatic guitar solo followed by that tense symphonic chordal thing). You've got the seemingly endless possibilities unlocked by technological advancement juxtaposed with the grim realisation that we're escaping our deyaying home planet, which I think is the sort of thing that would spark that sort of inner turmoil represented emotionally by this song (I know I'm kinda repeating myself here, but just to emphasise the point). Given the song's subject matter, I definitely can understand why the vocal melodies aren't typically hooky in the vein of The Enemy Inside or Untethered Angel, which feature more grounded, relatable topics and the melodies seem to reflect their own themes in that regard, too. However, I also think the melodies, while not accessible, are filled with intent and purpose all the same, though I appreciate that this is something down to personal interpretation.