I find that particularly interesting, as the "music first" policy seems to be the least common approach in songwriting (admittedly based on a tiny reference sample of maybe a handful of people I've ever heard speak about it.) If I remember correctly, Trent Reznor used that approach on The Fragile and afterwards said that it was incredibly difficult and that he wouldn't do it that way again (though given that The Fragile is head and shoulders above any of the NIN stuff before or since perhaps Reznor prefers an easy paycheck over quality results.) Nick Cave has, at various times, either roughly sketched the words/melody/structure of a song before having the rest of his band flesh it out or crafted whole songs before taking them into the studio where the band merely supplements the arrangement. Tom waits, these days, begins recording his songs with only the vocals and and maybe one or two instruments before arranging the music around that frame. Axl Rose is, off the top of my head, the only person who espouses writing the melody/lyrics to a finished track as the best method. It seems to work pretty damn well for him, but I'd bet that it's probably one of the central reasons for this album taking so long to write and record. Still, I'd rather wait a decade knowing that someone is sweating balls over making a good album than get a GNR version of "With Teeth" every year or two.
I dunno, I've always ound it much easier with my band to write the music first . REM say the same, the only song they've written lyrics first is Nightswimming (which
does have very good lyrics)...just my ?0.02