I was playing with my friend the other day, and we both made the same class, and we played that class at the same time with eachother; The difficulty with doing that is that it was hard to see how close he was to leveling and vice versa, like i know there is the ammount of Xp that you have, but i think it would be alot easier if there was a percentage ammount that would tell you the percentage of how close you are to the next level.
Anyways just a suggestion of what could be added to a patch or sometime.