The White Dwarf says that the intent was for this update to be official, but in regards to wraiths and banshees, it does offer the caveat that we are free to mix and match these new rules. That is, it seems to suggest that we can mix and match the two (Rare and Hero) or use them per WD (Hero) or per our Army Book (Rare).
Upon looking at the wraith, I was less than impressed initially, and to a certain extent the banshee as well. I love the banshee and her rules, but I feel that our Rare and Hero choices are so competitive that its hard to make room for anything that isn't a vampire (Blood Knights, Black Coach, Vargulf, Thralls) or a Wight King.
The nice thing is that now they can join units, and unless I am mistaken, the Banshee can use her wail as a Stand and Shoot Reaction, which might give some units a bit of pause (or hopefully damage em just a bit as they charge), so I actually intend to have at least one running around somewhere.
The wraiths I was less than impressed with, but I figured two things. One, both of these units cause Terror, which is nothing to scoff at though can be entirely situational. The next, is that they are ethereal. Someone runs up and issues a challenge and they better have magical attacks or you are going to have quite the fun challenge.
Its an interesting choice, and what I might end up doing, pending on how my shop takes to these new rules, is keep them as rare but use them as characters, or if I am feeling risky take em as heroes. I still feel that if your lord is a Combat monster, these won't see much use since you typically need your hero choices to fill in the blanks for your lack of a level 4 (or if he is a 4, you need them to play it safer since my Combat Lords like to 'splode on 3 dice :/).
