I think what Goldeneye means is to find a good balance, meaning bumping is okay aslong as you don't do it too often. (And if you do, it should be by adding new information, which isn't really possible in this case)
For now you can use "Edit Transforms..." to move things by a fixed amount. Not as convenient as dragging them all together, but currently the easiest way to make sure they're moved the same distance.
Also, I'm positive they'll further improve the way scenes work. Something I'd like to see personally is for "Edit Transforms..." to work on right-click more consistently. If nothing is selected and you right-click a source to go into "Edit Transforms..." it should let you edit the transforms of that source instead of giving you a greyed-out transforms editor because nothing is selected.