There is that kind ofroguery that is the dashing, swashbuckling, happy-go-lucky hearts and flowers ... and a darker sort that revolves around theft, murder, fraud etc. Look at the rogue skills and decide.
Then look at Vivec's past and strip away the fancy terminology.
What you have is a murdering, thieving rapist and he boasts of it. He murdered his own Hortator and friend and then married the man's wife. He swore not to partake of the heart and did so - stealing the Life's essence of a God. According to his own writings he taught the Daedric Prince of [censored] how to [censored] ... He lies in your face. He claims to be Mephala's son/daughter and what was Mephala? He claims to take her place ... Not sure how much clearer he could have made it.
Well okies, the only way he is not all of those things is if he is merely a liar ... so liar he is.
Now you may ask has he changed. I have no idea, but not on recent form. He is what he is and knowingly so if he has attained CHIM(p).