That's not really an argument -for- as it is a reiteration -of- your thesis. *Why* is that "they way it should be"? The way it "should" be, for 280 BC, is completely lacking in spaces between words, and probably written in all capital letters. I'm looking at The World's Writing Systems now, and according to it, "The earliest known handwritten Latin document can be traced to the first century B.C.E. Old Roman Cursive dates from some time before that and lasts into the third century C.E.". The majuscule vs minuscule distinction comes even latter than the advent of handwritten Latin.

So if you want how it "should" be, what you have (I think) is:

CAIVS·IVLIVS·KAESAR·OCTAVIANVS·AVQVSTVS

Also, your arguing in favor of using "v" throughout, but employing both "J" and "i" in your example seems to me like blatant hypocrisy. Maybe that was just an oversight, though.