Not really sure if composition is more important. Good bands should be able to make a balance between those two elements.
I might not have a soul, but I do like some of Malmsteen's songs - simply because I can imagine his songs to have a message - I can attribute some emotions to a music that may not have come from any emotion. Though anybody who is a virtuous in a instrument and spent a lot of time perfecting his skills, probably has just a bit of passion left when playing it.
However, by 'delivery' do you only mean just how well a song was executed? To me delivery also includes the atmosphere a song can create, what emotions a song can transmit to the listener. This type of 'delivery' can sometimes (not always) be more important than the composition of the song.
(Maybe you should have named the thread composition vs execution. Though it would be nice to take it into my idea of 'delivery' type of direction)
Just take a band like AC/DC or
Manowar ...or Korpiklaani. Their songs are rather simple, quite similar to each other, the lyrics aren't quite the
Epitome of poetry and
Genius, so the composition isn't complicated. But I think the way they deliver the song makes these bands what they are. People just love hearing these bands.
When in Danger or in doubt,
Run in circles, Scream and shout.