Before I go on to comment on the design's less felicitous aspects, the cathedral and architects should be commended for choosing forms that attempt a rapprochement with traditional forms, as well as for seeking to reintroduce the custom of burying bishops within the bounds of their cathedral. However, the incorporation of a crypt serves to underline the oddly contradictory and even somewhat superfluous nature of this addition, while the historical references incorporated within the design feel superficial.
While it is being called a narthex, that is precisely the one thing which the structure is not. A narthex is not a gathering space or overflow social hall; it is a place of transition from world outside to the heavenly reality within. It is a space, first and foremost, tied into the liturgical experience of a church. It is unclear to me how the addition will relate to the existing narthex, if the cathedral has one, though the presence of doors in the rendering and its placement off to the side of the first bay of the cathedral nave suggests it will substantially distort the way the cathedral is entered, and thus the way the cathedral is experienced; it will become a somewhat circuitous, sidelong entry at odds with the processional path traditionally associated with entry into a church.
The structure's octagonal, centralized typology, is also troubling. It is somewhat reminiscent of a chapter-house, baptistery, or even some monastic kitchens, though at a greatly inflated scale. From the few renderings I have been able to find, it appears disproportionately large next to the nave of the cathedral, and appears dangerously close to competing with it--it is too low and broad to appear like a tower, and too wide to seem merely an ajunct to the church proper. For a crypt or tomb-chapel, such a structure has precedents (one is reminded of the Medici tombs in Florence) but given the crypt is secondary and the principal floors of the structure are taken up with a mix of primarily secular and administrative functions, it seems inappropriate. If the builders wish to have a crypt, let them design a crypt; if they wish to have a social hall, let them have a social hall, but the mixture of these together, with a theater and toilets thrown in seems oddly indecorous, especially when cloaked in a centralized typology and profile that gives greater importance to the addition than it would appear to merit.
Lastly, as I have said before, the historical references, in addition to being somewhat misplaced, feel superficial. While an addition to a historic church need not merely ape every last detail of the parent structure, it should harmonize with and defer to its surroundings. The relatively simple renderings I have seen suggest typical modern detailing and fenestration. Especially when used in conjunction with Gothic structures, such elements can result in a design that feels like a caricature of Gothic, rather than an expansion of it. A truly traditional structure would have been preferable, but even, with a bit of imagination, a fairly "modern" design could have been attempted so long as the detailing and stonework felt in harmony with the existing fabric, resulting in something not unlike Lutyens' Castle Drogo, for instance.
Unfortunately, this is not the only project of this nature. Another similar and even more indiscrete addition, is being proposed at a different St. Mary's Cathedral, in Perth, where a whole new chancel is being contemplated. The design will convert a beautiful Gothic interior into the sort of in-the-round design that was au courant about twenty years ago, including, most curiously, what appears to be an octagonal altar wholly without foundation in liturgical law or twenty centuries of Christian tradition.
It always saddens me to read of such projects. There are many rising traditional architects, and quite a few established ones, who could have produced a discrete, elegant addition in a traditional style, or at the very least in a contemporary style that sought enough common ground with the existing building to not appear in competition with it. Even in the case of St. Mary's in Perth, a sanctuary re-ordering could have been attempted that brought the altar closer to the congregation without sacrificing its mystery, had the right precedents been studied. Comper, naturally, comes to mind. Such works would have been of international significance and of inestimable value for the growing restoration of the sacred. Instead, the resulting design will be just as expensive, and be indistinguishable from a host of other pseudo-traditional institutional structures and reorderings across the globe.
