Macbeth was a bad leader because he was not interested at all in the needs of the kingdom. He wanted to be king because he wanted power, not because he thought he knew what was best. He put his interests above the people’s, which is a terrible thing for a leader to do.
When you write a thesis statement, you need to be clear and direct and state a specific argument. In this case, you need to say both that Macbeth is a bad leader and give a reason why. Here is an example thesis.
Macbeth is a bad leader because he abuses his power.
You would choose how Macbeth kills Baquo, because now that he is king he does not think he will be caught.
To be thus is nothing,
But to be safely thus. Our fears in Banquo
Stick deep, and in his royalty of nature
Reigns that which would be fear'd. (Act 3, Scene 1, p. 42)
The fact that Macbeth’s first act as king is to kill one of his nobles is a pretty terrible thing. It shows that he does not care about his people. He does not want to have advisors.
Macbeth is also a terrible leader because he seems willing to kill anyone who crosses him, or whom he suspects of having crossed him. He slaughters Macduff’s entire family. He threatens his men with death if they say things he does not want to hear.
If thou speak'st false,
Upon the next tree shalt thou hang alive,
Till famine cling thee; if thy speech be sooth,(45)
I care not if thou dost for me as much. (Act 5, Scene 5, p. 85)
A good leader should be willing to accept reality, and act on it. Macbeth’s inability to really accept the soldiers coming at him must have cost his own soldiers many lives, if they did not desert him altogether.