I'm a student of law at the Universiy of Toronto, with an Hon. B.A. in Philosophy and Economics and a serious interest in Canadian politics, history, and music. I'm also a user-generated-content enthusiast.
Optimism should have a separate page that focuses on the philosophical idea of optimism and distinguishes the philosophical view from "positive thinking" and other everyday uses of the word.
Philosophy of social science, has some okay points but requires elaboration on Wittgenstein and Winch, perhaps other linguistic critiques, whether logical positivist or postmodernist.
Exchange value needs to be redone, it shouldn't be under 'Marxist theory'- although it's an important component of Marxist theory it's also vital for all economics. That said the article's weight on Marx is also absurd.
Socratic dialogues could do with some tidying and clarification. See the talk page for one suggested change.
Problem of universals: The introductory definition is (perhaps) fixed. But, the article is poor. Check out the German version.
Teleology: the article is shallow and inconsistent.
Existentialism: the quality of this article varies wildly and is in desperate need of expert attention.
Analytic philosophy This is a very major topic, but still has several sections which are stubs, and several topics which are not covered.
Lifeworld A philosophical concept that seems to have fallen exclusively into the hands of the sociologists. Could use some attention; it's a major and complex issue in phenomenology.
Perception Needs the attention of philosophically minded Wikipedians. This is only the start of an overhaul of perception and related articles.