When Mitt Romney launches his second presidential campaign Thursday on a rolling New Hampshire hayfield, notably absent will be a number of endorsers, donors and advisers from his 2008 bid who, for personal and professional reasons, have not committed to his 2012 effort. After running what was widely considered an unfocused and bloated campaign in 2008, the former Massachusetts governor is returning to the presidential sweepstakes with a more tightly knit team.