Isn’t that the point, in some regards? The urSkeks were alien invaders who committed genocide and caused widespread environmental destruction - it’s their ambition that drives the plot forward, it’s their powet and their willingness to wield it - without that, nothing would have happened on this wholesome sleepy little planet, you know?
How do you, as a Gelfling, navigate your life, in the shadow of these incredible creatures? That’s what the story tells - you worship them as gods, you treat them cautiously as potential allies or enemies, you rise in rebellion to eject them from your world - and maybe in the end you find a new peace and balance.
I do think that mystic and skeksis perspectives are present, in little peeks and glimpses, but I would still welcome another excursion into Thra to find out more about what their lives are like.