For the record I can't think of any U2 song I would call a gimmick (namkcuR's definition is a good one). I just wondered if anyone would agree with my 'claims' that Sweetest Thing, Zoo Station, etc. were gimmicks.
To make a few comments on your song analyses, you mention both intrinsic and extrinsic meanings. That is fine, but just be aware that w/o knowledge of why it was written, Sweetest Thing could sound blase. It's well written, but it doesn't say much that hundreds of other 'relationship' songs don't. That's ok with me, but people like zoomer probably don't think much of it.
Zoo Station has a TON of meaning when you take into account the band's new direction at the time. But it also has intrinsic meaning with a kind of 'carpe diem' theme, "Time is a train, makes the future the past/ leaves you standing at the station/ with your face pressed up against the glass"
Discotheque has plenty musical substance and meaning.
I found this very amusing. I notice you didn't try to explain it! I'll let you off the hook here b/c I find meaning in it too. Don't have time to explain though.
The main point here is that Vertigo is not a gimmick b/c it lacks meaning. It's main theme is temptation: "Your soul, it can't be bought/ but your mind can wander". For Christians, if your soul belongs to God, then Satan cannot take it. However, Satan is very happy to tempt believers and try to make them useless to God. Some religious imagery is thrown into the Club Scene: "The girl with
crimson nails has Jesus 'round her neck" (Cross necklace). Bono is a good boy
wink
and doesn't want to do the wrong thing, "It's everything I wish I didn't know" and turns back to God, "But You give me something I can feel". He does not give in to the temptation. The lines "All of this can be yours" recalls Satan's tempting of Jesus in the desert. (Out of curiosity, how many times does Bono say this? Christ faced 3 different temptations). Finally, the line "Your love is teaching me how to kneel" echoes the sentiment of Jesus saying "Whoever wants to be great must become a servant", and also the lyric from MW "If you want to kiss the sky, you better learn how to kneel".
So Vertigo is very much based on the concept of spirtual warfare. If do not believe in anything spiritual, then maybe you would think Vertigo has no meaning.