From the General Instruction of the Roman Missal:
“299. … Moreover, the altar should occupy a place where it is truly the centre toward which the attention of the whole congregation of the faithful naturally turns.”
It seems this is not being followed.
The GIRM also has: “291. For the proper construction, restoration, and arrangement of sacred buildings, all those involved should consult the diocesan commission for the Sacred Liturgy and sacred art. Moreover, the Diocesan Bishop should employ the counsel and help of this commission whenever it comes to laying down norms on this matter, approving plans for new buildings, and making decisions on the more important matters.”
Regarding the chair:
“310. The chair of the Priest Celebrant must signify his function of presiding over the gathering and of directing the prayer. Thus the most suitable place for the chair is facing the people at the head of the sanctuary, unless the design of the building or other features prevent this: as, for example, if on account of too great a distance, communication between the Priest and the congregation would be difficult, or if the tabernacle were to be positioned in the centre behind the altar. In any case, any appearance of a throne is to be avoided.”
Interpreting this presents challenges. If the tabernacle is not behind the altar, the chair of the Priest Celebrant should be centrally behind the altar. This would tend to obscure the priest from the view of the congregation, particularly when he is seated. A solution is to raise the Priest’s Chair on a platform. This tends to appear like a throne.
I think it would appear less like a throne if he were seated on the same level as others: concelebrants, deacons, instituted readers, instituted acolytes, altar servers etc. Perhaps the sanctuary should have one “working level” for the altar, ambo and credence table and steps going to a higher “seats level” where these chairs are.
The term “head of the sanctuary” also suggests to me at the back wall of the sanctuary.
The usual solution to the problem of the Priest being obscured by the altar is to move the chair to the side. If the altar is moved to the side it fails to be “truly the centre toward which the attention of the whole congregation of the faithful naturally turns.” (GIRM 299).
(I am quoting from the GIRM translation approved for Australia.)