What is it that makes armored core so bloody awesome looking, and so many other giant-robot mechas... not? (Like gundam)

Perhaps it's the detail, or the fact the heads dont always look like a goofy face. or how unique each and every single one is.

I think it's because the focus on the "weapon's platform" aspect leaves the humanoid resemblance is largely vestigial, so AC silhouettes are all greatly determined by their various "mecha" components rather than any one predictabley human shape.