Currently wikimedia.org is a non-wiki-style portal with three sentences and logos linking to the domains of the equally non-wiki-style Wikimedia projects. From those pages users can select a language version e.g. the wikipedia.org has links to the 280+ different Wikipedias.
However, what is missing is a set of portal subpages within the "wikimedia.org" domain that are organized by language and provide links to all the projects in a particular language. For example, there could be de.wikimedia.org, en.wikimedia.org, fr.wikimedia.org etc. Most would use two-letter codes but some would need three letter codes because there would be some clashes e.g. uk.wikimedia.org, which points to Wikimedia UK's website but the Ukrainian page could be at ukr.wikimedia.org.
Each language page would have a set of links to the different projects in that language and would highlight featured content in that language. A current example can be found on the English Wikipedia at w:Portal:Wikimedia featured content. Thus, en.wikimedia.org would showcase the daily/weekly featured content from English projects:
All the language pages would also show the "picture of the day" from Commons and the "species of the week" from Wikispecies. Obviously not all languages would have a full set of projects and some would not have featured content to display (yet!), but these could be decided on a case-by-case basis. The idea would be to provide a language-specific portal to give users a wider array of options when they visit "wikimedia.org".
The pages would not be editable (except perhaps by a few highly trusted users) but would otherwise look like wiki pages in order to make them more visibly like most content pages.