There seem to be issues with moving and rotating points using the normal Autocad commands. It can take a very long time.
I added MOVEPOINTS and ROTATEPOINTS commands to the Sincpac-C3D, and they work significantly faster - a set of points that might take 20 seconds with the Autocad MOVE command will move in less than a second with the Sincpac MOVEPOINTS command.
That doesn't help move linework, though. With the dynamic nature of C3D, moving things can be a hairy proposition. Sometimes everything moves just fine, sometimes there are issues. We generally try to make sure everything is in the correct place before we get too far into a project, and so far we've been lucky enough that this strategy has worked, except for once. And that one time, we were able to grab everything and rotate it with only minimal damage that didn't take too long to fix.
Since then, though, I've been shuddering over the thought of someday having a project with a number of drawings all linked together with lots of data references, and needing to adjust the coordinates (or even just the basis of bearings for the labels) for the entire project...