First, I must thank the people at Logos for the work they are doing for the Kingdom of God. I believe that the Preaching of the Gospel is better today then it was five years ago because of resources like this and workers rightly using them. Can you imagine If only Jonathan Edwards or CS Lewis had access to this?!
For my main suggestion, I think what Logos lacks is a good set of resources for music folks to use- sort of an expansion on the idea of the Logos Hymnal. I love to read Grudem and dive into an interlinear, but I wish I could search for 50 hymn texts on the trinity in Common Meter the way I can search the Post-Nicene fathers on the incarnation. There are many potential uses for hymnals that have music along with them, but even if we just made use of the many collections of texts out there, we could do so much for those who love to re-arrange hymns and use older hymns in their worship services. Perhaps a "Great Hymnody" collection could be sold that included many hymn collections like "The Psalms and Hymns of Isacc Watts," "Gadsby's Hymns," "The Trinity Psalter," "The Bay Psalm Book" (the first book printed in America, btw,) "The Book of Common Prayer," several denomonational hymnals, and even more historical works like "Slave Songs of the United States." They could be tagged with meter, subject, scripture association, author, genre, and other markers. This would be of great use to me as I look for good hymns texts to use in my church. These suggestions could also pop up in the passage guide where the Logos Hymnal suggestions often pop up.
Beyond that, we could take the actual music from these hymnals and allow capacity for them to be exported to a software like Finale. There, a user can change keys and otherwise edit a piece to fit their ensemble. If they are in the same meter, Logos could even export one hymn's text with the tune of another (try singing "Amazing Grace" to the tune of "There Is a Fountain Filled with Blood" to see what I mean.)
This would be most useful to me, but I do have another suggestion.
I was reading from the ESV Study Bible this morning and the notes at the bottom made me think of how easily Logos could allow me to take my own notes on the Bible. It sort of allows me to do that now, but what if we structured that to make sort of a "You" Study Bible that everyone could see online. Perhaps without the narcissistic temptation, though. It would be very useful if enough people started making notes on passages or verses and somehow we could search each other's notes online. This would be especially useful if some respectable scholars started using Logos and adding their notes. Who doesn't want to read Piper's notes from his study on Romans?
That's all I have for now. I hope you will seriously consider the hymns thing. It would be so helpful to me.
your loving brother,
-Dave Cook
Louisville, KY