I think the Orthodox could argue, especially based on an early and eastern perspective, that the term goes too far and is a manifestation of an overgrown ecclesiology. Having said that, St. Ignatius, for one example, says that we are "subject to the bishop as to Jesus Christ" (Epistle to the Trallians, 2), so I'm not sure where exactly the line needs to be drawn. It's probably the underlying ecclesiological principles that these titles and terms and statements represent that are the real issue anyway.