Kage Bunshin no Jutsu (影分身の術) literally translates into Shadow Clone Technique.
Is the word "kage" used to suggest that this technique was developed by a Ho-kage? Or does the jutsu have an actual connection to shadow?
You said the answer yourself in the comments: the "kage" part means the shadow clones...well, have a shadow. Regular clones lack substance and do not carry chakra, whereas shadow clones are basically copies of the person. Shadow clones carry and use their own bit of chakra that they receive from the original, so there is actual substance to them. The ninja way of summing this appears to be to say that "illusions do not cast shadows, but objects with substance do."
Generally it seems as though from a naming standpoint, a prefix to bunshin gives the clones some physical substance, whether is be water (水分身) or paper (紙分身) or something else. In my personal opinion shadows are merely quasi-physical in the sense that they are a lack of light in the midst of a more brightly lit surface, so it feels better if kage bunshin and regular bunshin were switched around. But hey, I guess adding the word "shadow" makes it sound cooler so it has to be the stronger spell.