Time to talk about skills for the combat part of the world. Some of these overlap into the crafting area, and I suppose I should explain that first.
Overlapping Skills: Ideally, the three worlds of crafting, gathering, and combat would be separate, with skills assigned for each. This would keep people from gaining skills useless to them. However, I don't think that is very organic, and it keeps the player rigidly in their current role. If you are a player like I am who likes to experience the whole game (and has dozens of alts to prove it) then overlapping is good. Overlapping allows you to switch to a different mode of gameplay with less downtime. Ultimately, people who do not want the skills they gain from outside their desired sphere can sell those skills (as described in the skill transfer section of the last development journal).
Weapon Skills: Weapon skills will come in two flavors. The first is a direct skill in that kind of weapon (two handed swords, bows, slings, etc). This skill will increase relatively quickly, and primarily has an impact on whether or not your attack hits. (Note; this skill has a chance to level up whenever used against an appropriate enemy, whether the attack hits or not. Most other skills related to combat require hitting the target or being hit). Each weapon type will have its own weapon skill associated with it, but the increased speed that this skill levels will make up for having to level multiple skills (and will also provide a good reason to stick with a weapon type you have used a lot in the past, and request that crafters make weapons of that type for you).
The second kind of weapon skill is the weapon family skill, or familiarity. Each weapon group will have a familiarity skill, and this is the carryover knowledge from working with a similar weapon. So, if you spend all day swinging a two handed sword, you can pick up a one handed sword without stabbing yourself, but you aren't as good with it as you would be with a two handed sword. However, this skill doesn't help you at all when you pick up an axe. The weapon family skill gives slight increases across the board for to hit, critical chance, and damage.
Defense Skills: Defense skills are the opposite partner to weapon skills. These skills are used when a monster attacks you. These skills all have a chance to level whether the monster hits you or not. This group of skills is broken down into the general defense skills (parry, dodge, and block) and the armor skills (unarmored, light armor, medium armor, heavy armor). The general defense skills do as they would seem to (parry parries removing all damage and counterattacking, dodge dodges avoiding all damage and block blocks absorbing some of the damage), while the armor skills determine how effective your armor is at mitigating damage.
Enemy Knowledge Skills: Each group of enemy mobs has two knowledge types associated with it. The first is [enemy group] knowledge and the second is [enemy group] anatomy. These skills determine your damage and critical hit chance/critical damage towards those enemies. These skills are gained primarily by attacking (knowledge) and hitting (anatomy) enemies of that enemy group. This is designed to represent how you should be getting better at killing dragonlings after fighting them for two months non-stop.
Overlap: As I mentioned, there will be some skill overlap. Examples of this inlcude the weapon skills improving crafting of those weapons. The full interactivity of all the skills (not to mention the specific skills and their primary attributes) have not been decided upon yet. Balancing a good number of skills with the attributes will be a long and difficult process, but ultimately a rewarding one.