I like the change that any set item less than lvl 60 can be crafted. This way you'll never need to keep a bunch of lower level items just to complete the set. It was always so frustrating looking for that last piece even though you would never actually use it.
I really like how set bonuses can be given to classes that can't use all the gear. Tal Rasha's, for example. Any class can get the "full set" bonus of having 4 items equipped, but only the Wizard can hold the weapon, with no additional set advantage.