Several people are reporting seeing the New Blogger GUI in their dashboard - even when they did not intentionally upgrade. Possibly, this was forced by the necessary Custom Domain Authentication Feature, which is now operational - on the New GUI only.
I am expecting my Blogger account to change, soon. Let's see if I get a "Your blog post published successfully!" display. So far, I am in Virginia - though I am thinking of a procedural workaround for that shortcoming. I realise that everybody won't have a workaround for their dislikes - though we have to be contemplative, and accept the changes.
If you wish to make your feelings known, please post in the latest Problem Rollup: V4 I do not like the New Blogger Interface because ...