Minor Description
The ClassicDependencyManager ignores the dependency management from transitive dependencies to maintain backwards compatibility with Maven 2, then Maven 3 (objective when extracting Aether was to keep compatibility).
The new TransitiveDependencyManager will use that dependency management: this new behaviour is expected to be a better choice. Once it is integrated into Maven core (version to be defined) as default new behaviour = a behaviour that is more predictible/logical, but that will break some previously working builds.
