They already kind of do that to my mage, I had some dead thralls that got glitched up or something, the thralls aren't even there anymore but now they always yell at me about keeping my magic away from them haha. I actually like it better everyone being afraid of my dark wizard than being friendly. Having people not talk to you would be ok, I just don't like the aspect of running for my life everytime I want to go shopping without casting spells on everyone.
Well if they did it like Oblivion, then the Volkihar vampires would have to just cast a charm spell on a person to be able to talk to someone, and this way people do not have to worry about being attacked. And it would be very similar to how they yell at you to watch the magic.
Pretty damn sure the guards would attack you, if I'm not mistaken. Stage 2 or 3 got "get away" comments, but stage four got you attacked.
No they never attacked me in stage four, and people would comment on how you looked sick at stage two and three. I have heard that if you talked to enough people while in stage four then the guards would come and attack you, but I have never had that happen before.