While reading PM books such as the PMBOK seems like the Project Manager should be a geek, a control-freak and a risk-freak, my experience shows that traits such as communication, laissez faire and courage bring a lot more added value and genuine leadership to the project. For example, some book explains that you should develop elaborate plans and check them weekly with your team for progress. That makes you master of Microsoft Project and other Office tool but gives you less time for being with your team. The Guerilla Project Manager however develops instead some high level plans and then plans in detail for the next iteration; he spends the extra time communicating with the team and the customer and having daily, 15 minutes or ad hoc status meetings.
The PM theory argues for a moderate, linear control of the project. The Guerilla Project Manager will vary the level of control required based on the criticality of the situation, the people that are involved and their role in the project. An obvious example is to give complete freedom to someone who is constantly respecting their tasks; it is unnecessary to add the overhead of external control to a person that is controlling their own activity so well. Less obvious is that you should apply more control to the team member that is a bottleneck (other activities depend on them). Spotting a problem early and finding help here can really make the difference. Even more subtle is exerting control over your client. Their lack of responsiveness can drag the entire team in a delay and usually there is a difference in the pace that your team can sustain as compared with the pace that the client team can sustain. Usually the client progresses slower then you, and that is because your project is just one side activity among many urgent todos in their daily job. What strikes me is that many Project Managers don't see this as their problem; they will complain over and over again about this but do very little to gain power over the resources of the client and instead expect the client will somehow correct the situation by himself. This however never happens.
In a Risk Management class of 20 Project Managers, I scored as the only person with a risk appetite, while all the others scored as highly risk adverse. This showed me that Project Managers are inclined by the nature of their job to be more risk adverse then it is beneficial. The state-of-the-art project manager should have risks assessed and contingency plans in place for all important risks; the Guerilla Project Manager will accept risks as part of the project, will see that there is an opportunity in every risk and will sometimes uncover risks (e.g. transforming them into an issue) in order to solve some underlying problems that might be a lot more painful to discover later on. Techniques such as prototyping are good at doing this, but it takes courage to show your client a quarter of an application that is still full with bugs or a team that is insufficient. However, for the later for example, having the customer complaining on this will bring upper management attention, which should instead help you get more resources. Great rewards lay for those who are willing to take the risks.
To close up, extroverted is definitely more valuable in the Project Management than introverted. Control should be apply wisely, where the most sensible areas are, and courage is definitely more advisable then being risk adverse. Since most of us are former programmers that used to have some introverted, geek side; and since people still believe traits such as being extroverted and courageous are born, here are some articles to help you change your mind: How to go from Introvert to Extrovert and Whatever you fear you must face.