One of the big changes is the additional high-level progression called the class mastery system. You are now allowed to split your experience points up between regular advancement and class mastery advancement. You can then choose to spend your class mastery points on new unique abilities, some for class, race, etc. The new abilities can really help make upper level characters more unique because there are so many new abilities available. Also it helps distinguish the races since some abilities will be unique to race. Unfortunately this system was still getting tweaked quite a bit so it's still uncertain as to how this will all balance out in the final game. Additionally, the level cap has been increased to level 60 and caps on statistics have also been increased.