I am really anal about using correct grammar, etc. I fully agree with children being taught and tested on their use of grammar and punctuation. I also think it's really useful to understand the basics of language structure such as what is a verb, prefixes, etc. All good stuff.
BUT really - what is the use of learning about present perfect, co-ordinating conjunction, etc. My year 6 dd is currently cramming this stuff with her class mates. Many of them are not good at writing and learning all this abstract stuff is not going to help them to write well!