I may well have said that or given the impression of having that view some time ago, but I have always been a big fan of the Foundation books (well, up to and including "Second Foundation" anyway). Psychohistory seems to me a bit implausable but a very entertaining concept and some of the stories are great. (I like The Mule especially). Asimov himself seems to have wilted a bit under criticism and later wrote Prelude To Foundation where he addressed the criticisms of psychohistory from the perspective of chaos theory etc... and 'demonstrated' in the fictional future that psychohistory would work anyway (I believe - many years since I read that one).

I also really like Ursula Le Guin's 'Ekumen' SF books and they too arise from social sciences insofar as they come from anywhere. The 'hard' SF elements don't get much explanation and the characters, atmosphere, cultures and societies are to the fore.