When using the rotate tool, it would be nice to have an option that you can default to that would place the rotation handle at the origin of a family that you might be rotating. This way families could be built based on the most common insertion and rotation point (seems that most already are).
If you wanted to relocate the rotation handle, you still could the same way, but the default location would be the origin of a family, not just the center of it.
And of course this wouldn't come into play when you have multiple objects selected.