There are several improvements but these two just caught my attention.
Shadowflame is causing a horror-fear effect for 6 secs now. 25 sec cd.
Warrior gains another 45sec cd ability which knockdowns an enemy and stuns it for 5 seconds.
Tbh, I am not a big fan of Cataclysm so far. I think the reduced talent trees are another step in the direction where in the end people will be smashing one big red button at the center of the screen (some classes already do).The whole expansion stinks of knockback, knockdown and gripping mechanics.I don't know..