The nave is long, with a deep choir and a raised, high altar of marble against the (liturgical) east wall[....] Originally there was a rood screen in front of the choir, and the communion rail was at the foot of the altar steps.Around here, the typical outer suburban/town church is in a Victorian (or occasionally Federalist) building that is almost without exception a much shorter high-ceiling box, with a tiny chancel pulled out of the east end. There is typically very little room to pull the altar forward, but that doesn't mean people don't try, no matter how infelicitous the result. My current parish, in being expanded, went from this sort of compressed space to a truncated cross according to the current fashion, in which the sanctuary is a squarish platform for the acting out of the rite, with the altar at its center. Twenty years into using this arrangement, and problems which became evident early on are still manifest. The arrangement has never accommodated the lectern/pulpit/ambo comfortably, so that in the end it has migrated inside the rail and is moved out of the way before the offertory. We have been reduced to dependence on amplification, which ought not to be necessary, but the ambo cannot be placed in an acoustically satisfactory location.
The presentation of the Cross as tabernacle and temple in the Book of Hebrews provided a theological rationale for this architecture. Because of Christ’s sacrifice we may go boldly into the holy of holies, to the throne of grace, there to receive the body and blood of the Lord and be made one with him. The building’s original architecture allowed this dramatic movement to be enacted in the liturgy, by passing through the Cross into the inner sanctum for the administration of communion.
There is,however, a deeper problem, a far more subtle lack which has only become apparent in watching a series of rectors cope with the space: it doesn't give any support to the liturgy. I have written before about how the 1979 liturgical rhythm moves so well with the tripartite neo-gothic space, and even in these small semi-rural parishes it works the same way. And this helps carry a priest through the rite, as long as they do not actively sabotage its solemnity. In our space, though, everything has to be carried by whoever is speaking or acting at the moment, because that person is on stage. The one thing that works well in spite of this is hymn singing, because there's nobody on then. And the thing is that I think at least communion could be improved by pushing the altar a foot closer to the retable and celebrating ad orientum, because then the celebrant wouldn't have to be on stage.
My high school chapel suffers the problems Harding outlined with his two altars, in spades. To cut them some slack, they were and are severely constrained by the need to fit more kids than the space was designed for into its utterly inflexible walls, but still, much of the mystery has been lost in its transformation into a liturgical stage. These little churches are scarcely less restrictive, as crowded as they inevitably are before the altar.
It would be possible to transform a similarly shaped space into a similar plan, but it's a lot of work, and it needs room, which is (again) precisely what these little buildings do not have. And simply pushing the altar forward a couple of feet and putting the priest on the other side is not going to convert these Victorian spaces into the supposed patristic model; what you get instead is the turn-of-the-millennium auditorium church, writ small. I've given my reasons for preferring ad orientum in general, the chief of which is that I think in this era worship does need to be directed outward at a transcendent God; but I don't think you get the symbol of immanence by moving the altar two feet forward and conducting the rite from the other side.