I forgot about the upgrades they added with the new books. I need to take a look at what they gave the Necromancer. I believe they made Castellans more "worth it" with the new book as well (they could work well but were hard to justify for what they cost) as well as point changes to spiders.
Minyakano, I find Dol Guldur a fun alternative army for Mordor based forces. Wild Wargs and Spiders are fast, flexible and effective. Orcs (LOTS) and Mordor Uruks are great foundation for the force. Some Morgul Knights or Black Númenóreans wouldn't be out of line. With the Mountains of Mirkwood right there you can ally in from the Moria list and remain well themed. And late in the War of the Ring, Sauron was sending large numbers of Easterlings to Dol Guldur for the attempted assault on Lothlorien so if you want some tough Men there as well you have a nice option (just don't think you can justify a Mumuk though
). It really isn't much different from what you can do with a stron Mordor list to begin with but has enough flavor to make it more unique.