How much have you seen of Coentrao because he looks half the defender that Marcelo was last season to me. There's no way that I would assume he is coming straight in to take Marcelo's spot. Seems strange to me but Madrid are a strange team.
Marcelo is only 23, played almost exclusively as a winger in 2009-10 and mostly got his games there in 2008-09 as well. Last season I would rate him as the (not one of) best attacking fullback in world football and easily top three amongst fullbacks fullstop that I saw last season.
Klaus, I would rate his attacking game as more expansive than Maicon's on last season's evidence. A little bit less dynamic and powerful but smarter and a better user of the ball and space.