I'd really like to see where my friends are on the map are - perhaps a different color dot for people on your friends list to make them easier to find when you don't have Eyeballery.
For example, I mine with a friend or two so we split up searching for rocks to mine, but it's hard to find the person when they call out a rock when there's so many other white dots on the map at the time. Being able to find your friends in the crowd more easily when you're split up would be really helpful!