Look at his whole design, look at the face (nose, mouth, chin), look at HOW he transforms (end of transformation he rotates on his hips to face his top torso forward) It's Beast Machines Primal!
Don't know about you, but I think movie Ratchet gives me a BW Rhinox feel. He busted out with his own minigun during the fight in the city, which left me total awe.
Yeah, Ratchet is awesome and does give me a Rhinox-feel to him, but I do see the Optimus Primal-like transformation in him.