Fair question and you've already received some excellent answers and if you reread them all for me, I agree with all they said.
1. Most are more difficult to sing. Traditional hymns are easier, much easier, the only problem might be if your voice can't cover the scale plus an extra note or two, and that goes for the modern stuff too.
2. Impoverished theology bordering on masonic, at least for the song I detest "Gather us in". With no mention of Our Lord, I imagine this being sung at Masonic Lodges. Compare the theology in traditional hymns vs the happy emotional sentiments of modern songs. Think of "Lord who at Thy First Eucharist didst Pray" "Crown him with many crowns" "Church's One Foundation" (yes, I know that was written by Protestant-it still works for Catholics) Father, We Thank thee, Humbly Lord We Worship Thee, Holy Holy Holy,
3. Since these poor songs bump better ones, I dislike them all the more. Catholicism is imbued with tradition and Tradition and the idea that one epoch of Church history, 1960 and on has the "best" music is preposterous. Sure, add a few modern songs, but most of them belong at that Sunday 5 pm Guitar mass.
4. I do like "Gifts of Finest Wheat" among modern hymns
Thanks for the answer, you're right I did receive some information. It was appreciated.
1. See my last reply. I'm sure it wasn't created for singing contests. I guess since I learned with the new stuff I don't really have the difficult to sing problem.
2. Actually when people kept writing about traditional songs, easier to sing, I kept thinking the lowest toned song I could think of off the top of my head "Gather us in". Upon further reflection, I guess you're right about its lack of liturgical mention. As far as older tone, I thought that was exactly what people were thinking. I've heard of and sung "Crown Him with many crowns", "Holy Holy Holy", and "Tantum Ergo", but the rest are unknown to me.
3. I can't comment on the songs they bumped, for I didn't know them.
4. Gifts of finest wheat is now stuck in my head.
"Gather us in" is indeed based on a Masonic song. A musically-trained friend of mine first heard it while passing by a California lodge.