I'm still very much a Wikipedia novice, but I am slowly trying to change that. I hope to take a more active role in the project as I get more comfortable with the whole process. I suppose the biggest areas I would like to focus on would be philosophy (and thought in general). I will probably end up contributing to some technology-based articles as well since I unintentionally educate myself in that area more than I care to realize.
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.