Hi dominik,
as to your question (sorry for answering somewhat belatedly): making the bounding box invisible while dragging the selected object works perfectly for me, too.
However, when the object which I'm working on is stationary and I just want to change some of its attributes – like, say, fiddle around with its stroke width or with a gradient or an effect that's been assigned to it – the bounding box with its blue lines and other marks becomes really obtrusive and it's sometimes hard to judge the effects of what I'm doing to the object in an unhindered way. This is especially true if that object is rather small but you have to see it in context with other elements around it (thus limiting the zoom factor used and leaving that object rather small on screen).
And while working on that object, I'll just HAVE to move the mouse (or pen) which immediately makes the bounding box become visible again...
As to your other remark:
I have Publisher and I checked what you wrote – it is exactly like you say (in InDesign it's just the same – and for good reason), BUT:
in "Preview Mode" everything that's not printing is hidden (as expected) EXCEPT for a selected object's bounding box! So we're back to the original problem...
In Illustrator, however, you have exactly what I'd really like Designer (and, for that, Publisher) to have:
in the "View" ("Ansicht") menu you can toggle between "Hide Corners" ("Ecken ausblenden") and "Show Corners" ("Ecken einblenden") which actually applies to selected objects. This way you can work on an object which then just shows "live" the changes you're making to it but doesn't show any markers showing that it's actually selected at the moment (but which you, of course, know at the time) – this way you're getting a true and unhindered preview!
Seems simple enough to me and I do hope the guys at Serif won't find it too hard to implement in the future...