Bernd,
you raise some very interesting points and the PMBOK certainly is a document that deserves some serious consideration. From the initial skim reading, I am not sure that I can call it interesting though

!
Solutions Reality has recently released Time Architect available from
http://www.timearchitect.net and listed on the EA 3rd party products page here
http://www.sparxsystems.com/products/3rdparty.html#TimeArchitect. We have already picked up the Resources tab in EA and built a tool that is capable of working with the fields in this tab but as 'live' fields not as 'dead text fields' as you mention.
For example, start date, duration, end date and time expended now have real meaning and true time calculations can now be performed accordingly.
From these fields you can now draw a fully interactive Gantt chart that is tied into the resource panel and the rest of EA. This means that when you allocate durations to an element, its end date is calculated based on the working day length, duration, vacations of the resource etc - before being passed back to EA. In addition, dependencies between elements are taken into consideration to help calculate element start dates etc.
This in turn ties into an advanced data grid that allows you to filter and manage the tasks - and therefore the EA elements that have become tasks. From this grid it is easy to see which tasks are finished, late starting, late ending, due to start and more.
As Time Architect runs inside EA, the tight integration means that it is just a simple click on the Gantt chart or the grid to get to the appropriate EA element to get the true context of the task. Likewise, clicking on an element in EA will highlight that element in the Gantt chart or grid so you can clearly see its context in the project lifecycle.
It is our intention to continue developing TA to become a fully rounded Project Management tool that sits over EA and works with all of the appropriate EA fields and brings true meaning to these areas of EA. We have a number of ideas of how this can be achieved, but welcome input from others as to what they would want out of such a tool.
We are currently working on version 1.2 of TA (we are trying to keep the release cycle short at the moment to allow input from our users into the development of the tool). 1.1 added the review functionality as mentioned above. 1.2 will add the ability to work on multiple tasks/EA elements at the same time - updating not only the resource information but key EA data too.
We will digest the contents of the PMBOK and see what can be added from this book and onto the roadmap for future development.
Anyone who is interested in Time Architect can download a fully functional 20 day evaluation version from the website.
Best regards,
Matt