Words are wonderful and the human voice is an amazing INSTRUMENT. But I completely disagree with the idea that lyrics make the song. It's only one (small) component.
Not when it comes to deciding if a song is good or bad though... you said you had music that was just instrumental, worshiping God. But if you didn't know the context of the song when hearing this, you would have never known what the intent behind the song and could have never came to the conclusion, "this is Christian worship music" just by hearing this tune.
If you have no lyrics, music is just noise. It's like if an atheist farted or a Christian did.. a fart is a fart. Music is music. Now sure people have different intentions when it comes to music. Some are to glorify God and others are to slander him. But if there are no lyrics, and you don't know the intent behind the music, there is no way for you discern what this was without someone telling you. So music on it's own is not bad...
And also I haven't read all the posts on here but it's clear most people making these sweeping statements about metal clearly have no clue about this music group. There are so many different sub genres to metal it's ridiculous. You can't say ALL metal is just harsh music and confusing lyrics. There is power metal, symphonic, melodic, progressive metal etc etc... NONE of those generally have lyrics you cannot understand or harsh vocals. They have more bombastic or harder elements but a lot of it is quite harmonic and has good melodies.
There are some genres of metal where I can see where people would think this is what metal is. Death metal always seems to have gruff vocals. And more banging sounds to the untrained ear. I could not stand this stuff when I first got into metal. Actually I couldn't stand thrash, or any really hard songs either even in the power metal scene.
The songs that got me into metal were slow songs. Metal ballads. The two songs that I first heard from metal bands were "Sleeping Sun" by Nightwish and "The Bard's Song" by Blind Guardian. Both are really slow songs. I really liked them so I looked by other slow stuff by these bands and others similar. As I listed to other songs by them, I started liking more progressively harder stuff... My music collection is huge now and most of it is metal from classic heavy metal to power metal to melodic... melodeath.. progressive etc etc etc. I can listen to a death metal band or a group with harsh vocals without needing to read the lyrics because I'm used to hearing vocals like that, I can generally tell what they're saying. So while YOU may not be able to understand it, someone else can.
And a lot of it is very beautiful and poetic. More so than 99% of anything on the radio. I found Christian metal bands that have so much more meaning and feeling than anything on Christian radio which sounds more like it was made on an assembly line than with any kind of genuine heart for Christ. Lyrics that actually look like it took some time to write.
Anyway that's my opinion and that's all I'm going to say on the subject. Music itself cannot be judged based on what you like. If I was being as judgmental about others taste in music, I'd have to say Southern Gospel is from the devil. I cannot stand southern gospel at all. Lyrics aside (cause were not looking at lyrics anyway), the music is terrible. And the singing isn't much better. You can say "it glorifies God though" all you want. What makes it glorifying to God? The lyrics? We're not judging songs based on lyrics remember? The music? Why? Because it's pleasing to YOUR ears? It sounds like crap to me and I would feel embarrassed playing that before God. Surely God would have better taste in music than that.
I like rock and metal. Just because it's not pleasing to YOUR ears, doesn't mean it's not to God's. I love it though. God said make a joyful noise unto the Lord. And that's what most southern gospel and CCM is IMO. Noise. But who am I to judge? You can make a joyful noise the way you like, and I'll do it the way I like. God judges the heart. Not how good or how bad the music is.
And in heaven, you guys can have your little corner of SG music and I'll be rocking out with the hard rock angels praising the Lord with GOOD music.
Peace