The kind of people that all teams need are people who are humble, hungry, and smart: humble being little ego, focusing more on their teammates than on themselves. Hungry, meaning they have a strong work ethic, are determined to get things done, and contribute any way they can. Smart, meaning not intellectually smart but inner personally smart.
I have yet to meet members of a leadership team who I thought lacked the intelligence or the domain expertise required to be successful. I've met many, however, who failed to foster organizational health. Their companies were riddled with politics, various forms of dysfunction, and general confusion about their direction and mission.
Meetings are the linchpin of everything. If someone says you have an hour to investigate a company, I wouldn't look at the balance sheet. I'd watch their executive team in a meeting for an hour. If they are clear and focused and have the board on the edge of their seats, I'd say this is a good company worth investing in.