The theme does not require the character to be a spellcaster. Bear warrior is a great example of a non spellcasting transmutational class.
Author of Path of War
My credits: Path of War and Path of War Expanded: An OGL Tome of Battle for the Pathfinder game system, for Dreamscarred Press. Psionics Augmented: Psychic Warrior and Psionics Augmented: Soulknife for Dreamscarred Press. My extended homebrew signature!