Although users wouldn't have to install those products by themselves (as they don't with w.dropdownmenu), I agree it does raise the CMS learning curve. But how could that not be if we'd like to give them flexibility to edit pages with aggregated content?
Besides, imo most themes have trouble achieving a complete visual identity without a frontpage that conveys styles for portlets or mosaic/cover tiles; those are the Plone equivalents to the boxes we see in most free templates. Without them, themes basically depend on just header and footer to display their visual message.
Otoh I don't think GSOC themes should include support for these addons, at least in their 1.0 versions, for the sake of simplicity. I just mentioned tiles for the SPA scope of medialog.bergensiana (and also because I suggested tinymce templates instead of them for creating SPA-like sections).