>>10758153I'm pretty sure the Ultra kaiju/seijin are being designed by autistic suitfags, which results in them getting really into minute details like texture, visible wear and seams, and engineering that reflects what the actual suit actor had to work with as far as mobility goes. And it really pays off.
Where as monsterarts seem to be more about capturing the idea of a given kaiju, trying to capture what the suit in the movie was trying to convey, not the suit itself. But there's a lot of room for interpretation there.