One other thing to point out, though, is that the composers who purposely took secular folk melodies or other kinds of secular melodies and turned them into either hymns, incorporated the melody into larger, secular orchestral works, art songs, etc, often times did not mean for the music to sound exactly like the original or to be performed like the original. It was meant to have a different “feel”. Some might have just liked the melody, itself, and wanted to use it for an “expanded” idea of the melody, or might have wanted to incorporate the melody into their orchestral composition to give homage to the beauties and strengths of his/her country, etc.
In regards to hymn melodies taken to be arranged for organ in certain compositions, I think especially in the past, composers understood or tried to adhere to the reasoning of “refining” the music for liturgical use. It could not sound secular. If Vaughn-Williams (who I personally believe was a great composer and did some really beautiful adapatations of folk melodies) for instance, kept the original rendering of the melody to “For All the Saints”, it probably would not have been accepted for use at mass or service - whether or not it was for an Anglican mass or Catholic mass. It had to sound different from what one would hear outside of church.
For most adaptations, I personally can appreciate the original form as well as the adapted form if it is well done. But I appreciate them in different ways and take them for what they were meant to evoke. I love old folk melodies in their original forms, but also love singing them in art songs. Britten has such an extensive collection of folk song arrangements and they are some of my favorites to perform. The same with taking of folk melodies and translating them to piano works, orchestral works, or adapting and refining them to sacred texts.
I will agree, though, that with “For All the Saints”, I have a tendency to want to take faster than how it is usually played. Although, when you hear one of those English choirs or even a congregation singing it full-voice with the organ supporting it, it’s like nothing else. That said, the Slane Irish folk melody and Kingsfold English melody (which Vaughn-Williams also did a lovely adaptation of) are both melodies which I love sung slower when set to religious text. And I love the organ adaptations to them, especially when played well. Brides have often used the Slane melody set to the “Lord of All Hopefulness” hymn for their processional and when my organist friend plays it on the organ, it sounds so beautiful and majestic, it brings tears to my eyes.
In their respective realms, depending on whether or not they are meant to be played like a folk song or a more reverent, spiritual way, the tempi taken are both great. I once used the Slane melody for my students to demonstrate how different a work can sound just by changing the tempo and making one sound more like a “jig” and then basing it on the text set to it, changing the whole feel of the piece by slowing the tempo, creating more legato. Of course, when played like a folk song, the kids were laughing and wanting to dance, etc - which is what would be expected. It sounds like a fun, secular piece of music. For the second example of the melody, though, they enjoyed it just as much, but in a different way. The hymn actually became one of the kids favorites to sing.
