I've filed a Workswith CQ per the Eclipse Third Party Dependency Policy  for Maven. Per instructions from Sharon Corbett, could the Mylyn PMC pleasediscuss/vote on the Workswith request via the PMC Mailing List?
To give more context, Mylyn WikiText provides a Maven plug-in. The plug-in requires all of Maven to run, including bits that are not a part of the maven-plugin-api (which already has approved CQ 7658). The missing bits of Maven must be installed by the user in order to run Maven with the Mylyn WikiText plug-in. In other words, the transitive dependencies aren't automatically downloaded by using/downloading Mylyn WikiText. It's also possible to use Mylyn WikiText without Maven for other things which aren't related to Maven.
The Maven plug-in provided by Mylyn WikiText was created as part of this enhancement:
420006: create a Maven plug-in for generating Eclipse Help from wikitext
Please let me know if you have any questions or would like more information.