I'll try to think through several of these issues--and imagine a way of framing writing as natural and writing as academic--I'm thinking of my friend, Mary here.
I'll say this about writing instruction (and I'm replying to Mary): if the way you are framing writing tasks and responses results in impelled writing, you're on. If it's writing as struggle (John Bean--may God forgive him), you're off.
Like Rich and Jan, I'm so much into writing as pleasure, as a way of materializing who we are and how we relate to those around us. If writing (a ghost for living) is a struggle, I think we're creating a destructive educational environment. I'm personal here: I have used writing as a way of understanding myself and how I relate to others. I think students like to use writing like this--and find out about who the others are, a knowledge that feeds back into our self-discovery.
So . . . if what you are doing is creating positive experiences for writing, you're doing the right thing. If you're not, you're not. Ask your students and you'll get a hint.