"I simply don't believe that continual flying by the seat of your pants provides a good education"
I used not to believe it, but then I met lots, and lots, and lots of HEors who took an autonomous approach, whose children knew loads, were enthusiastic, happy learners. And now I am seeing my own children do the same thing. There was some research published a couple of years ago about how efficient informal learning is.
Our local library service allows HEors full access to their library services for education scheme, for free. We do use it, but not much - we find that we can get far more information from the internet; museums; galleries; real life people etc.
And my children spend loads of time with other children. This morning my oldest and I took part in a weekly structured home ed group; tomorrow we'll be spending the day with my mum; on Wednesday my oldest goes to French club, and then we're all going to a rehearsal for a Christmas show with about 50 other individuals from HE families, and after that a 3 hour-long twice monthly social HE meet. On Thursday we're meeting up with HE friends. On Friday the oldest two do swimming lessons; then Badgers, while the youngest two go and play at their friends' house. On Saturday the oldest two have dance lessons. And after school finishes, they all go out and play with their schooled friends who live in our road. No shortage of time with other adults and children there!
I totally disagree that spellings have to be learnt - I am a very good speller but never had to learn them for tests. It just came naturally because I read a lot. My oldest is only 7 and is already a fantastic speller.
And socially, spending day in-day out with a huge number of people exactly the same age as you is not a good introduction to real life - at no other time in your life will you be in a remotely similar situation. The best preparation for real life is living real life - running errands with your parents; seeing them deal with relationships; having them guide you with problems with your friends; gradually taking control of their own relationships as they grow up.
I hope I don't mean to sound disparaging, but I wanted to show how your concerns about HE are not necessarily valid, Milamae. And, FWIW, our greatest supporters in our family are a primary school teacher, a secondary school teacher and a psychotherapist.