I'm excited to hear that the UI might be refreshed / redesigned. In my opinion, the PP products are overdue for an update to the look, which could help bring a more "web 2.0" type look. Something cleaner, with less visible lines, borders, tables, etc. Clean is nice.
So don't go overboard on the scripts for the presentation and extra features. Or, offer the option to enable all these extra JS
/AJAX scripts, social sharing buttons, etc. Have the "base" install as a good, clean, fast-loading code templates. I care more about a fast site than I do a fancy looking one. And so does Google.