He would have been fantastic in 2008 instead of Obama, liberals could have voted for him because he was black, conservatives could have voted for him because he was accomplished.
In 2016, no, the nation has black fatigue. We saw what happens with a black President and no one is in the mood for another helping. Unfair to Carson but his race will be an issue where it wasn't for Obama, the novelty has wore off. Electing the first black President is newsworthy, but the 2nd isn't.
As an individual, he brings no political experience nor management experience to office and he's not connected into the political ecosphere so he can't twist arms and bring alliances with him into office.
A good part of his appeal comes from misguided Republicans who've internalized liberal idiocy and are excited to be supporting a black candidate simply because he's black. There are thousands of white surgeons of high achievement in the US and no one touts any of these guys as ideal for President.