That's a mischaracterization. A presidential candidate who doesn't talk about uniting people might as well stay home.
No it isn't. That's always been his primary thrust. Go back and look at his first speeches and communications from right after his trial balloon went up several months ago. Pay special attention to his speech to the Lincoln Club of Orange County, California. Bipartisanship was what it was all built around, even to the extent of offering up a bizarre apologetic for the honor of Neville Chamberlain.