is it possible to render a html (preview) in the WYSIWYG editor in edit mode for dynamic content? E.g. instead of displaying the block [DynamicContent:ExampleDynamicContent], is it possible to display what this block is going to generate?
I Would not render it inside the WYSIWYG editor, since you never know what the dynamic content does, and it can be annoying to see the dynamic content be previewed each time you edit a page. Instead I would consider adding a preview link or button that opens up a popup with the preview (or something similar). To preview it you can either use the EPiServer Property web control or by parsing it (see Parse an EPiServer XHTML property with Dynamic Content).
Hope this helps.