I was thinking that to make this brand of orc, we need some universal rules for their army, and how they are going to affect points cost!
I was thinking of this for an animosity table, it won't be too bad, Roll on this table if you get a one. You have to roll this even if the unit is in close combat.
1- The boyz have gone haywire! Da horde is mutinising against undead power! The opposing player may control them in their turn as if they controled the unit. If a unit is charged by ths unit, at the beginning of the next orc and gobbo turn, the units are placed an inch away in any formation and direction you want, but can't move, shoot, etc.
2- Da light is calling da boyz! d6 boyz go to the light to bash some empire heads! Gorkspeed!
3- The boyz get d6 boyz in the unit but the unit has toughness 2 for this turn.
4- The boyz are undead! They shamble forward! key word on shamble! They may not march, fight with strength 2, and have leadership 2 for this turn.
5- Nagash is calling! the unit starts fleeing in the compulsory movement phase away from your opponents choice of unit. They automatically rally next turn.
6- The boyz become ethreal after drinking some foes blood. Re-roll this result if the unit has not reached combat yet.
I don't think we should go by the conventional undead rules, and try to orient them more around the CC aspect. For instance.
We still wanna fight!: For each model the unit boss kills, the unit revives one of the models slain by the opponent at the end of the combat, but before break tests. They don't get the Combat resolution for this model. If they didn't slay a model in combat, the unit can't revive models it did not have.
I think the regular undead unbreakable rule is fine though...