I like the "you're the bride, I'm your mother" analogy... it fits.

I think the producers role can vary, often depending on who is paying for the project and the type of market you're in. Example... I was an audio engineer/producer at a fairly big studio in a fairly small market (Charleston, SC) Most of the projects I did were paid for by the artist, so they had the final say in how aggressive or laid back I could be as a producer.

Now I live fairly close to Nashville, and am often there for work (not studio work, though), and I have a few friends who own studios there. Producers there are a whole different kettle of fish... often (but not always) quite aggressive in sculpting the sound of an arrangement. The producer/engineers I've met have all been amazingly talented folks, but I have heard plenty of stories from people who have been "put through the mill," spending a bunch of their own money & ended up with a fairly mediocre song.

Label-funded work is different... but I understand that is evolving quite a bit, and everyone says "It ain't like it used to be.."