Now, I have read all about how one should not use regular soap for shaving because of lather and slickness.

Those are two things I completely understand. In fact, one of the issues with most soap is it dries out the skin, where as shaving soap would not.

So, what are the issues or drawbacks, besides using it up, with using your shaving soap to wash your face?

I was thinking of practicing my lather technique every morning until I can get it down to 2 minutes with Williams, and yet I don't have to shave every day. Rather then let the lather go to waste, I could use it to wash my face.

The ingredients for high end face soap is the same, so I know that's not the issue. There is a difference in the amounts of those ingredients though.

I am talking hard soaps here, not creams.