I'm slightly concerned with what seems to be a pervading malaise here on the forum (and elsewhere) that "the old ones are the best and the new ones are all superfluous fluff".Personally I like the old hymns, the more miserable the better. And slow too , gives me a chance to play all the notes. I don't want them to die and I want my children to hear them.
What's good is good. Sometimes it's very good, and stands the test of time. Some of the hymns mentioned here are quite astonishingly old, and beautiful, in tune and lyric. However, some (many?) old hymns are poor - maybe even less worthy than the fluffiest of the new. And some, once perfectly acceptable, are now perhaps past their 'use by' date.
What I'm trying to say is - like everything, some hymns have their time. This 'elderly comfort zone' someone mentioned is a stereotype we should be careful to avoid falling for. Just because I'm old doesn't necessarily mean I like to sing only the hymns/songs I remember from my youth - far from it. I have recently started to notice that certain songs I liked as a child just don't cut it anymore, and this can mean any song, of any age. Some new songs don't cut it either, but some do, and if speed is not your thing, how about Quigley's "There is a longing" or Farrell's "Christ be our Light" to name but two. Such hymns seem effectively to bridge generations, and as such are highly inclusive, very Catholic.
Such are the songs - old or new - I feel we should be aiming to promote the use of, and indeed write, rather than trying to 'bag up' our communities into young, old and middle-aged. I really hate going to Mass and finding that everyone is old so the music is old, or it's a "family Mass" for people with kids, so the music is insubstantial - kids are smarter than that.
Don't use hymns because they are 'convenient'. Use them because they are right, for everyone.