Both instruments and voices are important to each other in almost all of today's worship music, unless you are a Mennonite/Amish or are an avid fan of Gregorian Chant. At the church where I was on staff for the previous 10 years, a cappela music (music without instruments) was repulsive to some in worship because the worshipers came out of a Mennonite/Amish tradition. This surprised me the first time I learned this. I thought they'd enjoy vocal more, but they associated vocal music without instruments with their former lives before they became believers.
You've heard me say a million times by now, the WORDS are the most important in evaluating any song. A song can sound great - nice melody and tasty harmonic structure, but the lyrics are what give the meaning to music. Without meaning, the music is amoral - or listeners will associate what they'd like based on past experience with the instrumental music.
The words in worship music must have theological integrity, otherwise it will paint a picture of God that may not be accurate with who God is in scripture. Therefore, it's the vocal end that gives life to the WORDS. If the vocals aren't clear, the words won't be either — and the ultimate meaning of the music will be skewed. For example, a vocal group (like
Spectral Voices, who records their harmonic singing in a watertower) that uses no words leaves the listener to interpret what one thinks the music means.
Instrumental music gives a further expression of the vocal/word part of worship. The instruments give color, create structure, and can bring about emotions (David playing a harp for Saul in the Old Testament).
Sometimes instrumental music can lead someone in worship without vocals. For example, when
Phil Keaggy plays his guitar - I'm amazed at how God has designed the human mind and hands to create beautiful music. Phil's music causes me to give value to what God can do through instrumentalists. Notice that I'm not worshiping Phil, or his playing, but how God has designed a mere human (Phil) to play.
So which is my bent? Well, I'm both an instrumentalist and a vocalist. But I'm a better instrumentalist than I am a vocalist. Because I'm better at playing instruments, it may give the appearance that I have more passion for instrumental music than for vocal music. It would be like saying, "Bryan is better at driving a car than he is at driving a Harley Davidson Fat Boy. His passion must be in cars - not motorcycles." It's not an accurate assesment, because I'd much rather be on a motorcycle. But I'm not a good rider. I am better at driving. The same goes for music. I'm a better player than I am a singer. It's just the way God has designed and equipped me.
In short, I value both vocal and instrumental music. I assign more value to the WORDS above the instrumental part of it, even though I'm more gifted instrumentally than I am vocally.