The three of us here at Guthook's Guides are in the process of making some major changes to the AT Hiker apps, along with all of our apps for the PCT, CDT, etc. We'll have new map options, better networking performance, and a few other improvements, which you can read about here for iPhone or here for Android.
Also, we're interested in hearing your suggestions for features. I can't guarantee we'll get around to all the suggestions, but many requests in the past have wound up as prominent features in the current versions of the apps-- like the elevation profile, the distance to waypoints along the trail, and the Facebook/Twitter sharing options. If you have something you'd like to see in the app, let me know and maybe we'll figure out a good way to add it eventually.
Cheers,
Guthook