I am a newbie and have never taken a class, but I would sign up as fast as I could for a class that taught a non-traditional block. One that would make a quilt that did not look like it had been constructed from square or rectangular blocks - where the construction was almost impossible to figure out. I would want instruction to make a quilt that I wouldn't find demonstrated in every LQS.
Whatever process - paper piecing, etc - this took would be find as long as the result looked unique. If others liked the blocked look, they could use sashings and fewer blocks.
I hope I'm able to explain this adequately. I wouldn't sign up for a class for a traditional type block unless it had a technique I wanted to learn to apply somewhere else, or unless I wanted the social atmosphere more than the teaching.