The transplanted hero
Sword and planet's defining premise — the hero from our world transported to an alien world — creates specific narrative advantages and specific craft challenges. The advantage is immediate readability: the reader experiences the alien world through a perspective that shares their own framework, and the hero's discoveries are the reader's discoveries. The challenge is avoiding the 'competence fantasy' failure mode: the hero who arrives on an alien world and immediately becomes its greatest warrior, without genuine learning or genuine struggle. The most compelling sword and planet heroes have something specific to learn from the alien world — a value or capacity or understanding that their home world did not give them — and their arc on the alien world is the arc of acquiring that understanding.