Scott Brown campaigned as a moderate independent but if you look at his record, he's a Republican who voted with Republicans 90% of the time in the US Senate until Elizabeth Warren announced her candidacy, and then he voted with Republicans on votes of importance 76% of the time.
No matter why you think he lost, you must consider whether the second most bi-partisan senator was still too conservative for Massachusetts.
Scott Brown's campaign for re-election was not about the issues. He sought to turn every issue into a character attack on his opponent, and had little to say about his own record in the senate or what he hoped to accomplish with another term.
Scott is a career politician with a very short list of accomplishments. His reputation of being a nice guy took a big hit during the campaign, and rightly so. A WNEU poll found that a majority of voters blamed him for the negative tone of the campaign. The other part of Scott Brown's image, his truck and barncoat, are in tact but they don't deliver when it's time to vote.