Going through the proposed writing curriculum, it's easy to see that it is massively complicated and mixes the 'micro' with the 'macro', the 'how' and the 'what' in ways that anyone anywhere would find almost impossible to implement - I mean adults or children.
What's going on here is a basic misunderstanding about how and why children might want to write, how and why they might change, adapt and develop their writing.
We get one glimpse of a humane and reasonable approach here in the Year 2 programme of study:
Reading whole books, not simply extracts, helps pupils not only to increase their vocabulary and grammatical knowledge but also to understand how different texts, including narratives, are structured. All of this can be drawn upon for their writing. 
Ensure that pupils understand, through being shown these, the skills and processes essential to writing: that is, thinking aloud as they collect ideas, drafting, and re-reading to check their meaning is clear. 
Drama and role-play can contribute to pupils’ writing by providing opportunities for pupils to play roles and improvise scenes, including those involving fictional characters. 
I am happy to highlight it - but why not expand and develop these 3 clauses so that the passage includes the idea that reading whole books involves an exchange of ideas and feelings between writers and readers and that's what it's all for! That's why teachers do clause 88. The children's feelings and ideas are the means by which their language develops and which enables them to write things that matter to them. So in clause 86 'reading whole books' has got its 'not onlys' much too limited. Yes, it helps children do these things but it also gives them a context and a pretext for thinking, imagining, wondering and debating! Whole books are like the opening lines for conversations - ones that you'll have either with yourself or with other people, in thought, speech or writing or all three. This is the fantastic generative power of reading whole books.
In actual fact, the document seems to be ignorant of - or has chosen to ignore - the massive research and qualitative literature that exists about creating rich writing environments, stimuli and 'situations' for children (in school and out) with outcomes in blogs, books, performance, school websites and so on. This sort of stuff is at the heart of good writing practice in schools with a library-full of books, papers, articles, pamphlets, journals which have been produced on the matter.
However, the document is precise to a point of obsession about spelling, handwriting and grammar.
Clearly there is a tension here - much more emphasis on correctness, treating the language that the children produce as exercises in producing correctness, rather than being writers expressing something they might want to say. Children in this context are not purposeful, reflective human beings for whom writing can have a role to play in their lives.
Be that as it may, the level of obsession about the 'how' of spelling, handwriting and grammar, if carried out to the letter, clause by clause, day by day, week by week, month by month, by schools, will doom children's writing 'achievement' to failure. It will inhibit their ability to write, it will inhibit teachers' from teaching and much of it, as Pie Corbett has pointed out here already, is impossible anyway. And we know this already from the levelling off of writing achievement that has happened as a result of the National Literacy Strategy. This is more of the same which will cause more of the same.
The heart of the problem is that though all people who devise these curricula from the board rooms of the DfE, are readers of some kind, they are not writers. Very, very few real writers have ever been involved in producing government documents on writing.
Why is that?
What's the matter with us? Are we ignorant about what we do? Are we short of ideas about the what and the how of our working and our work?
Given that people often ask me, well, what's the alternative to these documents and curricula? What would you do? I can say, without hesitation that a series of detailed workshops between writers and teachers and researchers would produce a set of documents and proposals suitable for every Year group in education that would knock this mess into the far distance.
It would be twenty times more useful, twenty times more creative, twenty times more appropriate and twenty times more 'rigorous'. It would be full of ideas about helping everyone WANT to write, but also full of ideas about all the questions of grammar, spelling and punctuation but in creative and interesting ways - because writers are people who have to solve those problems every day of their lives!
It would be a sensational mix of ideas FOR writing, ideas ABOUT writing, ideas about editing, 'getting it right', displaying, 'publishing', performing. It wouldn't be pie in the sky stuff invented at the DfE.
So when people say, what would you put in its place, I say, bang some real practitioners and researchers' heads together, see what 'proposals' they come up with and offer those to local clusters to develop and implement.
Then you would have a writing curriculum that would work.
This one won't.