You initially compared Zero's giant bugs to RE4's enemies, somehow saying that Zero's are more "creative in the full sense of the word"--they are literally just regular bugs... but made BIGGER. Regardless of what genre you think RE4 is, Regenerators are more creative and scary to most people over a giant bug in a video game. Not just from a character design point of view, but from its animation, sound design (the heavy breathing and music), and how complex it is mechanically.
I think you're trying really hard to play up big bugs as the epitome of creativity and scares the series has reached. If that's you're opinion, cool, but most people are gonna disagree with you when enemies like Mr. X, Lickers, Regenerators, Nemesis, etc. came after. Hell, even the bug enemies got more creative as the series went on.