Not just that, but taking the basic premise behind a cartoon meant for kids almost three decades ago and using it as the basis for a “serious” movie is absurd. Stuff like Teenage Mutant Ninja Turtles gets away with it because TMNT was originally a comic, and because the movies have a sort of tongue-in-cheek approach to the subject material.
But you’re right, the action sequences were terrible. There are better ways to do “large machines fighting each other.” Reference Macross Plus and Gundam 0083. (The staff of Transformers sure as hell didn’t.)
To me a story is all about plot (not a very good one), character development (one good scene, the rest a wash), and action (two spiders batting at each other ineffectually at high speed).
Action needs to be decisive and clear. When you can't tell where one robot ends and the other begins, when the fight scene doesn't seem to actually be accomplishing anything; what is the point?