This still seems to focus too much on what WYSIWYG is now, as opposed to what it could be.
Problem 1 can be solved by designing your WYSIWYG editor UI around modular page components and templates, kind of like desktop software designers like QtCreator.
Problem 2 is a matter of designing a good visual diff tool for the DOM. You could combine the Tilt Firefox addon with other visual difference tools like A/B overlays and highlighting changed attributes (e.g. if the text color or border size is changed on a particular element between two versions being compared, set the text or border color or size of that element to some highly-contrasting or even animated value when the element is hovered in the diff view).
Problem 1 can be solved by designing your WYSIWYG editor UI around modular page components and templates, kind of like desktop software designers like QtCreator.
Problem 2 is a matter of designing a good visual diff tool for the DOM. You could combine the Tilt Firefox addon with other visual difference tools like A/B overlays and highlighting changed attributes (e.g. if the text color or border size is changed on a particular element between two versions being compared, set the text or border color or size of that element to some highly-contrasting or even animated value when the element is hovered in the diff view).