A constant NPC companion, like a wise-cracking beetle, for comic relief would be fun. But I suspect that two of the threads of the GoaT experience are loneliness and disempowerment. This is why we have a tiny minstrel mouse (not a mighty, muscled warrior) on his own, arriving at the dangerous island of Periclave on a quest. I think this mouse will puzzle, stealth, and battle his way alone, for the most part... so brave and cute! Perhaps for another game, but I still like the idea of a wise-cracking beetle though.
The island of Periclave seems like an exceedingly dangerous place. I imagine that a lot of the neutral inhabitants (NPCs) of Periclave will be cautious of strangers, possibly a bit hostile at first. Perhaps they eke out an existence by foraging, and keep well-hidden from the dangerous factions, like the skeleton rats. At the beginning, they might pop up briefly every now and then, just barely seen as a flicker of movement, as they watch the mouse and try to figure out his intentions. If they think you are ok, they might carefully leave guidance or a cooked meal in your path.
Evilking, I know what you mean about the romance angle too. It is a staple of movies and videogames to have a romantic interest embedded in the story. I know Seith has the insight to avoid cliche, so it will be really interesting to know how his take on this.
I also really like the idea of meeting a chatty fish, who is bored and lonely in his pond. He is a pleasant, roly-poly character who just keeps on talking.
If it is technically realistic, it would be cool to have some NPCs who are so big and powerful, that the scurryings, problems and conflicts that the smaller creatures have with each other are irrelevant. Elsewhere on the forums, Raggon suggested a goat. I imagine these bigger creatures to be slow-moving and sage-like, perhaps wise, but also annoying to any tiny creature who is embroiled in the conflict and suffering on the island.