Having played a few of the undead lists quite a lot lately, I'm not sure I understand the reason for the nerf. While I think this does bring in line a hand full of units that seemed too good (Mummies) this is going to really thrash the heavy hitters that don't see the benefit often, and actually seems like it is going to make mummy spam more the viable path. Why isn't their a cost for undead tied to quality? Maybe a discount for high quality models it hurts and a premium for low quality units that rely on it.
Speaking of the Undead rule, over time we’ve found that this has become one of the most valuable special rules in the game, and that it gave a little bit too much staying power to your units. In order to balance things out a little, units now take wounds from Undead on rolls of 1-2, instead of only on rolls of 1.
The ability to outright ignore morale tests and thus never be Pinned or Routed is very powerful, especially when it's negative effect was only the loss of 1/6 models. By changing the potential loss to 2/6 models, we think that the effect feels a little more balanced now. This has nothing to do with point costs, but it's more about the game feel.
Gotcha, if the undead are meant to favor the poorer quality units for army feel that makes a lot of since. The high quality monsters are a lot more risky if they aren't bubble wrapped now, which will force them to play a bit differently, which will be cool.
True, but that means every lone wizard, archer, kid with a rock, etc, can kill a large monster below half with a single shot quite a bit easier now. Doing the 4th wound on a 6 wound model via ranged attack will kill it 1/9th of the time rather than 1/36th, making it much more frail, regardless of quality or armor. I'm not saying its a bad change, mummies were OP, but this will make minor ranged combatants a threat at any size, which may not be a bad thing.