Henchmen – many systems have mook rules, Savage Worlds uses Extras, and D&D4e has minions. I like the concept and prefer it to the “all Goblins are created equal” old school method. In reality, the PCs shouldn’t know by looking at a bunch of Gobbos at a distance if they’re a bunch of hard boyz or if they’re just weedy little mooks. Identifying the leader may or may not be easy at this point. Leaders usually have the best gear, so if the PCs have time to observe the group before becoming engaged with them, they may be able to spot this or they may be able to pick out who seems to be bossing the others around. After combat starts it’ll be clearer who’s calling the shots.
Henchmen Work Together – in practice, most GMs treat groups of mooks in combat this way anyway with the melee weapon armed mooks going in for melee attacks while ranged weapon armed mooks look for good shots; here they’ve just codified it. This also prevents a group of three archers from taking down one foe with the first attack in the group and then having archers 2 and 3 select another target. Since they are acting on the same initiative, you assume that all the attacks made by a group are simultaneous. So yes, they all have to attack the same target and by concentrating their fire, they just increase the chances that at least one of them will hit (represented by the single roll with additional fortune dice for extra attackers). Much more realistic that assuming that 3 archers acting on the same initiative still act sequentially and can react to what their fellows are doing/have done in such a relatively short span of time.
Henchmen have fewer wounds – It makes sense that henchmen will be easier to take out of action than a “regular”. D&D’s rules for minions does this by having all minions have only a single hp so that a single hit always takes them out. This seems to be a little better system for one that uses HP/wounds. Some henchmen may still fall to a single blow, but others might take more than a single hit to deal with. I like it. I am concerned that the difference in wounds is the only difference. They’re only easier to kill in combat. In all other ways they appear to be as effective as a “regular” of their type.
Henchmen share health – This presumes that in the swirling mass of combat, you are not only being attacked by a group, you are attacking the group. This is a reasonable compromise between always removing a henchman with a single successful hit and having to track wounds for them individually. Combined with the fact that some henchmen may survive a single hit, but they always attack together, in essence, attacking a group of henchmen is just like attacking a single creature with multiple attacks that for every x wounds has its attacks reduced 1.
PCs engaged with both NPCs “regulars” and henchmen will have to decide whether to allocate their attack(s) to the individual(s) leader types, or the group. In practice however, it seems it will always be more effective to target henchmen rather than “regulars” since the rest of their stat line remains the same. For example, in melee vs. a regular foe with 15 wounds and 3 henchmen with 5 wounds each, assuming one attack each, you can reduce the number of attacks against you by one for every henchman you take out, so by causing 15 wounds, you remove 3 attacks and now are only facing one from the regular. Focusing on the leader means you have to do 15 wounds to remove his 1 attack, which is no more effective than those of the henchmen, and are still facing 3 attacks from the henchmen. This is just in combat though and it may well be that there is some other benefit to taking out the leader first (like forcing a Morale check on the henchmen).
Aggression, Cunning, and Expertise – Looking at this, I’m wondering how this works with henchmen. From what we’ve been shown it is only wounds that are reduced for henchmen, meaning a group of 3 Chaos Marauder henchmen have 12 fortune dice in combat. Are all the dice contributed by individual henchmen added to one big pool or are they tracked separately? If the GM used 2 dice during the first round of combat and the PCs take out one henchman, does the GM have 10 fortune dice left (assumes a single pool), 8 (assumes tracked individually and the henchman removed is the one who already used 2 of his dice), or 6 (assumes tracked individually and the henchman removed is one of the two that has not yet used any dice)? Since wounds aren’t tracked individually, it follows that fortune dice wouldn’t be either. This gives the GM more flexibility to spend them when and how he chooses (tracked individually, you’d be more prone to use them before you lose them), but may cause heartburn for players who see dice continue to be used that were contributed by henchmen they’ve already defeated.
Enemy Threat Level – This seems to be combat oriented and smacks of D&Dism. I won’t get into a discussion on whether or not WFRP should or shouldn’t be concerned with enabling the GM to create “balanced” encounters. However, by itself the skull designations don’t provide enough information. Are four one-skull creatures the same threat as two two-skull creatures or is it some other scale? Is it impossible for a one skull physically weak creature that is cunning to be better in a social encounter than a two skull creature? Is there a skull to average PC advance table somewhere in the Tome of Adventure?