This has been extensively discussed in many threads... As many find these issues problematic, Additionally even the shift drag (without option) will often result in an inaccurate placement. On a complex layout, FileMaker grid snapping is beyond horrible in FM12, I always have to hold the command key to override the snaps, as they are completely counter-intuitive. And as to the multi-selection info, this is also a time drainer...
As to the "Themes" I suppose they may help some developers who are graphically challenged, but I personally find them dreadful. In addition we have no official control over the CSS.
On the plus side (having spent some serious time rebuilding layouts for FM12)... The new capabilities to control the look and feel of layouts is simply fantastic. If you have a good graphics background, you can easily achieve a far better looking interface than you ever could prior to FM12.
Two voters to bring back the Shift-constrain behaviour!
This is coincidentally the thing that I've tried to do a dozen times just today (and no matter how many times I do it, it still doesn't work), and it is the reason I came seeking out this topic for discussion with Product Managers.
But this discussion of layout mode changes also needs to cover the reasoning behind other undesirable behavior changes: the inability to resize multiple items without their positions also changing, the change in lasso-ing behavior when selecting objects, inability to get left/top positioning when multiple objects are selected, the continued inability for Inspector size and position fields to 'select all' when entering, the continued lack of keyboard shortcuts or context menus in conjunction with the hodgepodge that is the Inspector, etc.
Paste in Place would be another good option.
Then you can drag and constrain after that. The paste it close but not in the same place is a MS Powerpoint mentality that I wold GLADLY be shut of.