294. The People of God which is gathered for Mass is coherently and hierarchically ordered, and this finds its expression in the variety of ministries and the variety of actions according to the different parts of the celebration. Hence the general arrangement of the sacred building must be such that in some way it conveys the image of the assembled congregation and allows the appropriate ordering of all the participants, as well as facilitating each in the proper carrying out of his function.
Active participation, not only of the choir, but the assembly:
The faithful and the schola cantorum (choir) shall have a place that
facilitates their active participation.[Inter Oecumenici 97-98]
Con-celebrants need not strain the architecture of a building, but there should be accessibility for them:
The Priest Celebrant, the Deacon, and the other ministers have places in the sanctuary. There, also, should be prepared seats for concelebrants, but if their number is great, seats should be arranged in another part of the church, though near the altar.
Hierarchy, coherency, and accessibility: these are all important virtues. But the Church also proposes unity:
All these elements, even though they must express the hierarchical structure and the diversity of functions, should nevertheless bring about a close and coherent unity that is clearly expressive of the unity of the entire holy people. Indeed, the nature and beauty of the place and all its furnishings should foster devotion and express visually the holiness of the mysteries celebrated there.
It’s almost always possible to express all these values. I think unity is the highest value, (it is credal, after all) and it would have been laudable to place it first among these others. The other mentioned in this last paragraph, sanctity, is also high up on the list. Not only is that credal, but it is one of the two express purposes of liturgy as laid down in Sacrosanctum Concilium 7.
Your diocesan building or art commission will certainly be aware of these. If a church’s architect is not, then it is incumbent upon the pastor to ensure all these considerations are put into play when designing and furnishing a church building. And whether he functions in this way, or hires a consultant, or designates the staff liturgist, this is a point of catechesis and faith formation for the entire faith community.