Relief carving commonly seen in the sacred art of the Eastern church (I have written about this here). Its limited three-dimensionality ensures a flatness that suits the intention of the iconographic style to portray the heavenly realm, which is outside time and space. I would love to see artists from the Roman Church following the example of their Eastern brethren and producing relief carvings in Western forms. The most obvious place to start would be to develop the Western iconographic forms, such as the Romanesque as there are close parallels with what the East has done. However there is relief carving in more naturalistic forms too. Ghiberti worked in the period when the Renaissance and the gothic overlapped and to my eye, the polychrome reminds me of a gothic carving, while the bronze relief seems to have aspects of a classical naturalism that points forward the masters of a hundred years later.
The reason that relief carving might be effective today is that the strange world that it occupies, which sits somewhere between two and three dimensions always seems to lend to the image a symbolic quality. This would help to counter the great disease of modern naturalistic styles, which is sentimentality. All Christian art, no matter what style, involves a balance between naturalistic appearances and idealism (or stylisation) which communicates invisible truths (Pius XII talked of a balance of 'realism' and 'symbolism', in Mediator Dei). The tendency of artists today is to swing to the extremes. Those who wish to paint or sculpt naturalistically tend to forget the symbolic content; and I am suggested that relief carving would push them into including it.