There is earlier post with similar title, but there is no useful answer. Problem is really simple, you cannot teach laymen to paste from the HTML tab! It's just impossible! The paste buttons for WP / Plain text are great, but that is extra complication, I want default to be "paste as plain text" or "paste from word".
Current default for WP creates pre-tag when pasting is next to useless to almost anyone who doesn't happen to be coder (or have monospace fetish).
I'm in process of setting up WP network for one client, and I'm certain that I will get a lot of silly calls from my clients every-time they cannot do this and that. This happens to be the biggest mis-feature in WordPress so far.
It's either this pasting bug or the extra step required to set Featured image (uploading is not enough, one must remember to click the link set as featured image, duh)