Kudos on this beta version of Publisher. Many very nice features already and eagerly anticipating ones not fully developed (import of IDML files, anchored graphics, GREP, EPUB3 [without the InDesign bloat], hyperlinks, etc).
I work with several clients who, in addition to print versions of their manuscripts, also offer interactive PDF versions. There are often requests for interactive buttons where the expression of hidden text/images is triggered by some action, for example a mouse rollover. Is this type of functionality being considered?