I don't think there's a right answer, as long as the product works. When I was first starting the hook was paramount, because I felt then (and there's probably some truth to it) that without a strong hook that the song wasn't worth keeping around. So, I'd either write to the hook (often in a chorus), or wait until I had one sufficient to be a keeper and then structure a song around it, but as time has went on I've learned that it's...at least for me...a limiting prospect, and doesn't always work.
For instance, there are melodies that are so strong or catchy that they kind of form their own hook...a pattern that is sweet enough, or lands sufficiently before repeating that you can write the song almost without a hook, if that makes sense. Other songs, for reasons of meter or structure, might be plodding along with just a root note or two, and the hook comes along and opens it up and really sells it.
I think just being open to the melody and making sure the lyrics work around it will answer those questions for you, on a song-by-song basis.
