They're richer, fitter and not as politically liberal as they were 10 years ago, but they're not so sure they're any happier. In a survey done for their 25th reunion this year, members of Harvard College's Class of 1956 say more class members than ever before "express second thoughts about various aspects of the path we have taken to reach wherever we are today." More than 40 percent of the 664 alumni completing a questionnaire said they could not call themselves "contented" or "blessed" despite a class median annual income of $60,000 and an average net worth of $300,000. Only 59 percent said they would choose the same careers today, down from the 75 percent who said in another survey 10 years ago that they were satisfied with their work. "Perhaps a reflection of midlife crisis, perhaps regrets deriving from a longer time horizon of introspection, perhaps some jealousy of the wider choice of lifestyles available to today's young people," was responsible for the shift in attitude, wrote Stephen Greyser and Timothy Ellard, members of the class who helped compile the report. Half of the class called itself liberal in 1971, but now claims to be politically moderate. Eighty percent, however, said they supported women's liberation and almost the same amount opposed using "any and all means" to defend "our way of life" anywhere in the world. "One of our great shifts to the right comes in our attitudes toward whether government spending and massive federal programs can cure our social, economic and industrial ills," the report said. More than 25 percent of the class reported earning $100,000 or more annually; two-thirds earn $50,000 or more. Nearly half voted for President Reagan, but 80 percent said they were uncomfortable with "the role of government in our country today." Three of four graduates still were married to the mates they started with, and 75 percent said their wives are working now. More than half claimed they weighed almost as the same today as they weighed when they graduated. They also said, as a group, that they smoked less and cut down on drinking alcohol.