What is this idea of "singability" in worship music? I've heard so many different points of view on this that I thought I would share my thoughts on the issue.
As far as music style, it is marginally true that some songs are easier to sing than others. The most significant variable that affects singability is familiarity. Hymns are some of the most difficult songs to sing when one is unfamiliar with them, due to the lyrical syncopation and accents that often run counter to normative diction (for example, the word "fortress" in "A Mighty Fortress is Our God" is sung in three syllables, requiring a sort of double tonguing of the first "r", not easily done unless you are familiar with the song, and one of hundreds of like examples).
And the debate on singability runs to and fro. Many who prefer hymns argue that choruses are "too simple and repetitive". And while modern/postmodern worship music is increasingly embracing hymnody and returning to values of complexity, intricacy, and depth in worship music, those who prefer simpler choruses argue for singability. And while there are good points to be made on all sides, in the end it truly boils down to taste and familiarity and circular logic. "I like what I know and can sing and worship to easily", "I can sing and worship easily to what I like and know", etc.
The idea that some songs are more worshipful or more conducive to worship than others is a truly flawed proposition. Worshipfulness is in the heart of the worshiper. Everything on the exterior is taste and familiarity. Hymns are not better or worse than Hillsongs in any spiritual way, nor are Hillsongs better or worse than Vineyard or SixSteps in any spiritual way. The only way they are better or worse than each other is in the way that they meet people's expectations and tastes, or put another way, in the particular language that they speak to particular people. You can read my post called "Music as Language" to learn more of my opinions on this idea.
However, I do feel that some songs, and especially certain lyrical styles, are better suited for leading worship. I believe that ALL music is worship. But not all music is best suited to lead others in worship. For example, I could write a song with lyrics about being addicted to drugs, and how I trust in God for deliverance... and when I sing that song, I would definitely be worshiping God with it. But it might not be the best song for me to use to lead others in worship. Certainly it could lead others to worship, and it would perhaps be awesome and powerful for those who could connect with it somehow and worship through it. But it would take a special connection that not everyone would have. So I see a slight difference between music that is designed and written for personal worship versus music that is designed and written to lead others in worship.
At the same time, during a church gathering there is definitely room for all kinds of music and worship styles. I have experienced great connections with God in personal worship through experiencing the talents and personal worship of others, even if I am not participating in it, but only watching it. When I hear an awesome guitar solo in church, it moves me to worship God all the more because of the amazing talents and gifts of creativity that He gives to us, and for the way that others use those gifts to worship Him. I don't have to participate in a guitar solo to be led in worship by one! But it is my personal choice to worship God for what He does. Some people might get distracted by a guitar solo, or be tempted to give praise to the soloist instead of the Creator who gave the soloist the talent. Some might make judgments about the soloist, assuming that he or she is looking for praise. Instead, I worship God for the talent He has given the soloist, and in my own way I join with the soloist in worshiping God. My assumption is that he or she wants to give God glory by soloing. That is AWESOME to me.