Blue post sul forum USA:
There is a tier 4 set for most builds for each class. The boss drops a "token" for a certain slot for a certain set of classes (it's not really called a "token", but I'm speaking of it mechanically here), which you then turn in for the type of set piece of your choice (ie: for a warrior, the tanking plate or the dps plate, or for a druid you choose between the healing, moonkin, or feral gear).
in pratica il t4 non sara piu "unico" ma ogni classe avra a disposizone piu varianti dello stesso set a seconda della spec.