When I am using my iPhone, selecting skills to learn is very difficult. When I tap on a skill, it activates the hover phase, and when I finally get the "Learn This Skill" window with the button to pop up, the hover state with the skill information never disappears.
Adding a "learn this skill" link on the hover state when user is in iPhone or other mobile would be super helpful. Obviously you can't play a lot of the game from mobile devices, but learning skills is something I keep track of and start a new skill once my old one has finished no matter where I am.