Skills in Dark Heresy were designed by Andrew Kenrick, whilst T.S. Luikart designed a plethora of Talents. Here, both of the guys describe how they approached the work.
Andy Kenrick: Writing the Skills chapter posed some unique problems, because it not only had to convey the rules, but also had to give an impression of the various Skills in terms of the setting. If the emphasis is placed too much either way then the chapter could have ended up as a dry list of rules with no connection to the Warhammer 40,000 universe, or, perhaps worse, a 'flowery' background chapter that obscured the rules for the skills themselves.
A good starting point was the skills chapter in the Warhammer Fantasy Roleplay rulebook, which opted for short, punchy skill descriptions. I adapted this style somewhat, expanding the one-line description into a slightly more substantial paragraph that included examples where the skill might be useful, specific to the Warhammer 40,000 setting and the role the acolytes have within it.
Certain Skills are grouped into distinct types, for example Investigation and Interaction. Investigation Skills are the essential backbone for Inquisitorial scrutiny and clue gathering, and a guide to using such Skills details the differing complexity levels, test difficulties and time required. Broadly speaking, the Skills described range from the mundane Basic Skills like Awareness, Climb and Intimidate, to more esoteric ones like Forbidden Lore, Psyniscience and Tech-Use - all of which are highly desirable for any acolyte character to have.
As with every aspect of the game, it was important to make the skills feel as though they belonged in the Warhammer 40,000 universe, and not any other setting. I think we pulled this off - when you look at your character sheet and see skills such as Psyniscience, Medicae or Forbidden Lore (Xenos), you know you can only be playing Dark Heresy!
T.S. Luikart: Black Industries more or less publicly let on that Dark Heresy's RPG engine was 'built' using Warhammer Fantasy Roleplay as a starting point. While that is true, Dark Heresy is an entirely different beast than WFRP. Sometimes, the smallest changes to mechanics can create a world of difference in how a game plays.
Case in point: let me tell you about one of my favourite Talents. It's called Hardcore. Well it was called 'Hardcore' at any rate. That's what I called it. BI made me change its name. Apparently, Hardcore means different things to different people and Dark Heresy is poised to make its way into a fairly wide number of countries (and languages) so it ended up being called Combat Master. So what does Combat Master do? No matter how outnumbered acolytes with the Combat Master talent may be, their opponents get no bonuses for outnumbering them. If you're brand new to Dark Heresy that may not sound like much, but trust me, if you were an old WFRP player, your jaw may have just sagged a bit. Combat in WFRP is all about taking advantage of an opponent (or being taken advantage of!) and outnumbering a foe is one of the surest ways of bringing an enemy down.
Not always in Dark Heresy.
A simple change, but one that can make a 'combat character' far more effective in holding off masses of heretics, xeno scum and cultist hordes as befits the bloodstained glories of the 41st Millennium. There are a wide number of other Talents with similar small changes that result in an extremely different game. Spoilt for choice is what your PCs are going to be.
So remember many months from now, when your acolyte is getting swarmed by dozens of feral warriors, you look your GM in the eye and tell 'em, "No combat bonuses for them, I'm Hardcore!"