I’ve been a Microsoft Project Server consultant and trainer since 2002. One thing that I (and my colleagues) have felt is that there appears to be no clear direction to where this software was heading. Case in point, Project Server has been married directly with SharePoint Server from a software, business and marketing stand point to this day. It originally made sense because SharePoint is used as the platform of choice for Project Server.
But when you think about it, Project Server is really a Line of Business (LOB) application. Even the definition from Wikipedia “…critical computer applications perceived as vital to running an enterprise” would suggest it.