Well, I suppose you could say that the foundation of all poetry is ambiguity... and the beauty of it lies in interpretation.
Lyrics are so much more fascinating when they function on several levels - and feature layers of connotations.
That said, hooks do tend to be simplistic and repetitive, and I do love a good hook. However, catchy lyrics and intelligent/thought-provoking lyrics do not need to be mutually exclusive, I believe. It's great fun trying to write stuff that's catchier than an STI, but also compelling, and with a degree of complexity.