The obvious action and excitement tend to occur mainly in the final act, especially when Macbeth comes under attack. Much of the earlier excitement and action are psychological, especially in the lead-up to, and aftermath of, the killing of Duncan. Shakespeare seems to have been far more interested in the ways minds think and hearts feel than in the actions of physical bodies.
I would say that Shakespeare's drama does offer excitement and action, but not in the traditional sense. It is not swashbuckling or sensationalist. Yet, I think that the action and the excitement resides in the corruptibility of human beings. There is a level of excitement in the action of watching Macbeth plunge into unspeakable levels of depravity. His lack of remorse in this process is a part of this action, and helps to enhance the viewer's shock, where excitement lies. Macbeth is a character where a definite study in how human beings can become motivated by irrational forces. His desire to appropriate the world in accordance to his own subjectivity is a part of this excitement. I think that "excitement" in this sense can be defined by the triggering of a reflection within the reader and audience. It is here where I think that there is action in the drama. There is violence in the drama and there is confrontation, where excitement is present. Yet, I think that the real action and excitement lies in a moral and internally subjective manner in which the reader is able to engage in a reflective process in seeing Macbeth and wondering how his/ her own life possess parallels or points of divergence.