EA had the following summary on hwo advancement works in Warhammer: Age of Reckoning.  If you are an avid experienced MMO Player, none of this is really anything new, but always good to confirm that the rules haven't really changed.

Advancing Your Character

Everyone starts out at Rank 1. As you do quests and kill things, you gain experience. As xperience accrues, your rank increases and you start to learn some of the ins and outs of your career. As you gain ranks new abilities will become available to you and your character will increase in power naturally.

Your character can be advanced and customized in a number of ways in addition to gaining Ranks, abilities, or new weapons and armor.

Morale
Morale abilities are powerful effects that require you to engage in combat for a period of time as you gain Morale. When you use a Morale ability any Morale you've built up is lost. There are four ranks of Morale Abilities. Rank 4 Morale abilities require the maximum Morale possible (100%) but can be devastating to your opponents. Players unlock their first Morale ability at Rank 8.

Tactics
Tactics are passive abilities that can be combined with other tactics to enhance your natural abilities. As your gain ranks you unlock more slots to use additional Tactics at the same time. In addition, you can save different sets of Tactics for use in specific situations. Players unlock their first Tactic ability at Rank 11.

Career Masteries -General Overview
Career Mastery will allow players focus on different facets of their career giving them the opportunity to differentiate themselves from others, while still making sure that every character, no matter how they're specialized, can still perform the basic and fundamental purpose of their career. For example, every Sword Master will be an able tank, capable of absorbing much more damage than a lighter fighter. However someone who specializes in the Sword Master’s defensive path will find that they are generally more durable, able to hold aggro better in PvE and able to defend their friends more efficiently in an RvR scenario. Meanwhile a Sword Master who chooses to go a more offensive route will still be able to take a hit, but may find themselves hard pressed to defend & protect as well as their counterpart, admittedly they will be hitting quite a bit harder as a trade off. To begin at the most basic layer, every player will have four grouping of skills: Core skills and skills that fall under one of three different Paths of Mastery. The Core skills include a small handful of abilities which are simply critical to the career (to continue the example above, a Swordmaster would find that their Taunt and Guard abilities are Core).

These Core skills automatically improve as you gain ranks; once you learn them, they won't require any further investments. Moving beyond that, each career will have three paths available to Master, each of which emphasizes one specific facet of the career's abilities. While the Core skills represent a more automatic progress, the pathed skills are heavily player-controlled.

Each Mastery contains Base skills, Supplemental skills, and also has its own Mastery level. Base skills are the Actions, Tactics & Morale a player is granted as a reward for achieving a specific level, every character of that Career will always be able to purchase these skills, however their total effectiveness is intimately tied to the player’s level of Mastery. Supplemental Skills are the Actions, Tactics, and Morale that a player can only unlock by increasing their Mastery of a given path, like Base skills Supplemental skills continue to increase in effectiveness as you’re Mastery level increases. The Mastery level itself is the current amount of Mastery a player has in a particular path, players will be able to choose just how much Mastery they desire in each of the three paths available to them.

Earning Skills & Increasing Mastery
Skills can be earned in one of two ways Base skills are unlocked when you achieve a specific rank then purchased at your trainer, players can choose to skip a Base skill if they desire but there is no good reason to do so. Supplemental skills however are only unlocked once you reach a certain Mastery level, once unlocked a player has to choose to spend points to purchase these skills. This is a difficult choice because the same points used to purchase Supplemental skills are used to increase Mastery level. These points are referred to as specialization points, and are earned every rank, a player will never have enough Specialization points to completely Master multiple paths while purchasing Supplemental skills. It is a tough choice because every point of Mastery earned improves EVERY action in that mastery line by a small amount this includes the Base Skills you automatically get. One level of Mastery can seem trivial however they add up and 5 or 10 points of Mastery makes a significant difference!

There is some amount of automatic leveling of power for skills in the paths outside of their Mastery. This is done to make sure the ability is not completely useless to the player, in fact many abilities may still be useful for secondary effects such as Stun even if they have horrible damage/healing values because their Mastery level is lower. When comparing the general power of an ability of a path with 100% Mastery and one with 0% Mastery you will see around a 30 – 35% difference in power. Remember this number can be improved (or widened) further depending on which Tactics and Stats you focus on as well.