One thing mainline DM vendors have traditionally been good at is reference-oriented publishing. For example, Documentum has focused on regulatory compliance processes. Now XyEnterprise (long known for its SGML and other publishing tools) has released a new version of its CM product, Content@, geared specifically for editorial workteams managing product documentation. As the pace of complexity grows in the CM software space, maybe some of their competitors will also be Content@'s first customers...
See the XyEnterprise Press Release