I don’t have first-hand experiene of this - church design and soforth - but it certainly is not a case of merely hiring an artist and setting them loose on the church. I imagine that the usual process would involve long deliberations between the clergy of the parish and probably the parish council before looking to a suitable artist or architect. As far as I can see, Canon Law doesn’t give many specifics (though I expect other documents probably do); it says “Can. 1216 In the building and repair of churches, the principles and norms of the liturgy and of sacred art are to be observed, after the advice of experts has been taken into account.” However, as we all know, the “norms” of sacred art have been stretched to the limit with ambiguous and abstract works - I personally don’t think that the Faithful should have to struggle to discern the possible meaning behind artwork in the average parish church.
Once the parish itself has established a vision for where they want to go in terms of church design, they would seek suitable artists or architects (bearing in mind that the process could be drawn out if planning applications have to be made). There are some artists who are well-known for producing high quality church art. Certainly, a name familiar to many Irish people (although he is dead nearly 80 years) is Mr Harry Clarke - he created the most wonderful stained glass in Ireland and abroad, and there are still artists of the “Harry Clarke School” who continue to produce fine stained glass in his style. So there are definately church art specialists out there and they would be the most obvious ones to consult. Once the church authorities have spoken to some artists of good repute, I expect they would outline their vision for the church and the artist could produce draft plans until both sides are singing from the same proverbial hymn-sheet. Obviously an artist will have to express his own style - but there would have to be some constraints, such as the possible effect on the general character of the building & of course they would have to be correct theologically and scripturally. Unfortunately, money is probably the main reason why many churches are left with mediocre artworks.
Regarding your reference to the stained glass window being behind the altar “instead of the Crucifix” - do you mean to say that there is no crucifix in the sanctuary area? There is no requirement to have a crucifix on or behind the altar, but every church is to have one somewhere near the altar - a stained glass window of the resurrected Christ cannot replace this requirement. It does seem odd to me that a resurrected Christ would not be depicted with the wounds of the crucifixion - does it definitely depict a post-resurrection scene (i.e. could it be showing the Transfiguration or some other scene)? Can we assume that this is a relatively modern church (or artwork) - one perhaps where we want to show people the joy and glory of the Resurrection but want to hide the horrors and pain of what went before: I must say, that wouldn’t surprise me in the least…
