If Sanders hadn't run, would Hillary have done better in the GE?

[°Leprechaun]

GOP candidates weren't exactly nice to each other, ignoring the 11th commandment. Both parties have deep divisions, and I have always had a problem with the two party system. Would something like IRV or something else change this? Does negative advertising really make sense? Why insult the intelligence of the American people? Certainly partisan supporters of candidates are much worse at being civil, even than the candidates themselves, but many Americans are capable, if they wish, of discussing politics with more logic and civility. The problem is that nasty elections are more interesting than nice ones would be and the media loves drama. (including, I might at Fox news (aka Trump news)).