I assume there's a relatively straightforward solution for this using the Editor Options area, but I've not been able to find it. Could someone provide me with the way to have a WYSIWYG field default to visual rather than text in the WP Editor? I'm fine with Text, but the client is likely to find it intimidating.
It looks like WordPress saves the last action of the user with the tab of the WYSIWYG field (include the content in Classic editor mode). You can try to switch to the tab Visual, save the post and check this field with another post/post type.