Although I do so admire and appreciate the difficulty of bringing an instrumental piece to life, many times I feel something's missing. Like why is that piece called Moonlight Dancer? I think it's supposed to inspire that feeling from the music. Many times I don't get it. I only remember a few top instrumental pieces that have survived the years, some Mozart or Beethoven pieces, maybe a Stevie Rae Vaugh or a Hendrix.
Many instrumentals are great background music for a nice dinner or relaxing or making love. But as a lyricist primarily, personally I find the imaginary of words and a good vocalist who can express the words add so much to the completeness of a song. A perfect marriage between the lyrics and the music. Just as a poem seems incomplete with out the music, so does an instrumental piece without words.