What should a student do about a professor who uses class time poorly?
I would encourage you to view this not as poor teaching style, necessarily, but as a particular teaching style which may not suit you.
You should not take for granted the fact that this teacher actually seems to care about the material and be excited about it. That is a great opportunity for you to learn and you should take advantage of it if you can. Ask questions, try to gain some of this person's intuition and insight into the topic - you are probably paying for access to this professor, and this is a way to learn things you cannot learn from the book.
You should describe the teaching style in any reviews you submit about the course or professor. Some students would love the type of course you describe, and some (such as yourself) will not find that it meets their needs. This is the proper way to give feedback. Complaining to the administration will probably not be effective because the professor is not doing anything wrong (except perhaps running classes too long), just adopting a particular teaching style.