Changing classes because of bad lecturer??

Hey guys, i'm kinda new here so let me know if anything is out of place.

I'm in Junior Year of college now, major in Fina/Econ. I am taking a class now with the same lecturer who takes a senior derivatives paper I was planning on taking. However, I find his lectures and assessments very vague and irrelevant; i.e. tested on material not covered in any course materials, and assignments with little or no direction given. I have a good record to date but I am struggling in this class, along with most of the class.

My question is, would you consider changing a class you planned to take because of the lecturer/assessment structure?

Thanks!