Users that perform SPARQL queries only occasionally will benefit a lot from content assist and query help. An example is the Wikidate Query GUI. The assist not only consists of SPARQL syntax but users can also search subjects, predicates and objects suggested based on a keyword search (the user only has to know the namespace). The quiery help provides similar functionality and helps users build queries step. Implementation components can be found on GitHub.
It would be great to have this functionality both in the Web interface and Stardog Studio.