I think you pretty much nailed this one! The mini is such a great likeness of Christopher Lee, but you have really done well on the robes, and the face. Maybe a few dirt stains along the hem line? Then again, I don't think I would mess too much with it. Leave it as is. Good job...
This is a good miniature, but there is not enough variances. I think that if you use more colors for painting, you could have a better result.
Maybe with some blue on the staff stine, and more shadows on the cap ?
Good luck !