Every day I hear of people who have received their results and are disappointed to have achieved 6.5 in writing because they needed 7.0. Also, every day I am asked to advise whether to apply for a remark.
First, most people achieve higher scores in the other three modules. Here are the world averages for 2017:
Listening 6.17, Reading 6.02, Speaking 5.88, Writing 5.55. There is a simple reason for this. Almost everybody speaks a language, including their own, better than they can write in it. It’s true of me, my mother and most people I have ever met.
Second, IELTS scores map onto CEFR levels. 5.5 is at the bottom end of B2 and 6.5 is at the top. So 6.5 is a good upper-intermediate. However, IELTS 7.0 is C1 and therefore proficiency level. There is a BIG difference between B2 and C1 and 6.5 and 7.0. At 7.0 you need to demonstrate a variety of complex structures and produce more than 50% of your sentences without any errors in grammar, punctuation, spelling, collocation & connotation etc. This is really difficult and it needs a lot of practice to get right.
Before you ask for a re-mark please get a sample of your writing checked professionally. The BC/IDP don’t often make mistakes but it does happen. And finally, I can promise you that there isn’t a conspiracy to award everyone 6.5 so that you all have to take the exam again.