So I saw this on n0m's last update, looks like he's added the capability for a right click menu on skills:

I thought it would be really cool to add a right click menu option for "show experience bar".

This could add a movable window on screen that shows how far you are to your next level for that selected skill.  I've found myself checking my experience countless times while leveling to see how much longer I have until my next level, and having to pull out the calculator and subtract and divide to see how many actions I have left.  I think it would be cool to just have a bar that slowly fills as you gain exp.