Haven't really thought about it that much, but I think you guys are right; Cyborg's form here really drives the point on his body having been replaced by a machine, unlike his usual design, which would probably look more like a suit over his human body; the visuals of this iteration are a little shocking, but I guess it's necessary to make the point about the character and his conflict, the whole "am I still human? Am I alive?" thing as both Red and Wolfie pointed out.
This also gives me the impression that the tone of the film won't be "marvelized" as some feared, but it won't be too dissimilar from the previous movies (just sliiiightly lighter)
Polux