Others already noted that we need contrary opinions more than contrarian people per se. Let me make another distinction. Is the goal a community with a diverse set of opinions, or more people who are vocal and articulate about some minority opinion? Maybe the latter goal is worth working on, but I suspect the former has already been reached. Let me go with myself as an example. I don't think anybody ever saw any of my comments as contrarian, and I am sure nobody associates my nick with contrarianism. The thing is: I would bet against Many Worlds. I am not a consequentialist. I am not really interested in cryonics. I think the flavor of decision theory practiced here is just cool math without foreseeable applications. I give very low probability to FOOM. I think FAI as a goal is unfeasible, for more than one reason.

I am not vocal at all about these positions, and you will very rarely see me engage in loud debates. But I state my position when I feel like it, and I was never punished for that. (I don't have any negatively voted comment out of a few hundred.) I think we would see a similar pattern when checking the positions of other individual "non-contrarian" commenters.