Not many change of relevence to us, but this is a nice addition: labels on path lines. Other changes are listed here.
"Labels are now turned off by default in Google Earth 6.1, but you can add them at the midpoint of regular lines by using the new<gx:labelVisibility> in a <LineStyle>. Here's an example KML, as well as a screenshot above."
Comments
I'm sure Michael Oborne will be devising a way to include them in the kmz log exported from Mission Planner.