In what way do you want Moodle to be semantic or more semantic-web ish?
Much of the data within moodle, has activities related to people as well as documents or media etc. In that Moodle works largely from a database there is already an ontology (naming and categorisation) applied to the data & users contained within. Further, The more recent Repositories allows items or objects "to be" and referenced to by moodle where ever they reside on the Web. Flickr , Youtube & Mediawiki are obvious examples.
Some objects within Moodle exist within a namespace a course and category already and as such have "ontologies" associated with them, and the oft seen breadcrumb trail and navigation blocks provide a contextual ontology though not as such coded within the page, but displaying the categorisation in the main screen.
Further work is I gather being done to enable Moodle as an LTI provider and client which in some way provides Moodle courses and activities as a semantic object addressable and usable by another system to transfer information and actions across the web. The most likely path to contribute to Moodle in a semantic-web way would surely be to enhance its connected-ness to the rest of the world: repositories, Links, sharing, hubs.
Given that Moodle is most often used with a logon to access, I would doubt the value of developing a module on its inside. Maybe focus on the linking abilities to and from the rest-of-world.