Of course a manager needs to be a leader, a guide, an enforcer. But a manager also needs to be a supporter. And I mean that in every sense.
I do not just mean in the obvious usage of cheerleading or defending her team from criticism, though both those attributes are critical too. But I also mean support as in assistance to help do their jobs. When someone gets stuck in their work, when they cannot resolve a problem, it is the manager's responsibility to clear that blockage. And that takes knowledge, of the problem specifics and if necessary of the appropriate additional resources required to resolve it.
Clearly not every manager is going to know more of the detail of the individual jobs and tasks than those who report to her. But if she does, then I say that is unquestionably a good thing. Knowledge is definitely a positive attribute. Narrow-minded thinking and prejudice are clearly bad qualities, they may be positively correlated with experience; energy and enthusiasm are clearly good qualities, they may be negatively correlated with experience; but again, knowledge itself is a good thing.
That is not taking away all the other qualities necessary for leadership, basic human qualities still preside. But I could not write a post called "supporting your team", as I did yesterday, without stressing this particular one.