Had you forgotten about the Diablo III Q&A stream about the Necromancer? Because that happened. Not to worry, though; there’s a full summary available for those who missed it, going over all of the important questions. For example, Necromancers will not get 7-piece item sets, specifically because the developers want to retain the identity of sets and mixing and matching pieces eradicates that.
This is not, it seems, the answer many players wanted, but it is an answer.
Blood is Power and Bone Armor are both receiving changes as well, as it was possible for testers to more or less become wholly invulnerable with the right loadout. Players who jump between platforms for the game will also note that the Necromancer pack is not purchased cross-platform; you’ll have to buy it for every platform where you’d like to play a Necromancer. You also will not be able to increase the total amount of time your pets remain up and active. So that collection of answers may not give you the answers you’d really like to hear across the board.