Oh lemme see here....
Each class is having up to 10-15 skills completely reworked!
Many lower skills are going to provide passive benefits to higher ones. This is like how the druid wolves and bears add defense, damage and life to each other.
I dont know whether I like the fatalist new unique gem. It does look like they are going to implement some powerful attributes.
Some assasin skills are going to based off a percentage of weapon damage so they can maintain usefulness at higher levels. I would assume they will do this to other characters as well.
I really cant believe they are doing this much work to it. The 2 programmers working on it rewrote the way skills are organized by the game. It seems now much less of the skills are hard coded, making it easier for modifications (official and community ones). They have to have something up there sleeve.