I've found that the Danse Macabre can be really overwhelming for an elite opponent. Using onslaught on the Necromancer also makes his ranged attack pretty scary as long as you have the doubles for it.
I personally like the board control I get out of the skeleton horde list, I've been playing with Necro, 2 Seneschals, 2 Champs, 2 WG with Shield, and 4 sword skellies and I'm 2-0 so far. I know that's not a lot of battlefield experience, but I felt like I had the upper hand even losing a few skeletons here and there. Tying people up in combat with 2 Seneschals and then using Danse Macabre was a death sentence to a leader/elite both games.