Thanks for your reply.
By navigating using keyboard arrows I did not mean to move objects (which is nice too) but to move the view without having to use the scrollbars.
The most important thing for me would be the zooming though. If the location under the mouse cursor stays the same while zooming, one can easily navigate by zooming out, moving the mouse cursor and zooming back in again. This would allow to navigate through large models quit, and when done, the cursor is exactly where you need it.
Another point, is it really necessary to have the "Set Magnification" event in the Transaction History? If I change a table, zoom out, move around, zoom back in again and then find out, that I would like to undo the changes on the table (using Ctrl-Z, not the Transaction History) then I've got to undo all the other steps before, which did not affect the diagram at all.