SOE also redid character models, offering new customization options and making some changes that lower the models' system performance hit. You can keep your old look if you want, though.
The most controversial changes are a whole slew of class damage adjustments. SOE looked at every single class in the game and adjusted its damage output to ensure "that each lands in their correct place in the spectrum of classes." The details of all those changes are buried in the patch notes. Did you get nerfed or buffed? Read up to find out.