I'd imagine it's a way of (1) adding more shared skills and (2) providing role labels for them. Hopefully in the process we'll see broader and more meaningful cross-class choices, such as more powerful defensive options for non-tanks (better than the RNG-dependent and mostly negligible Keen Flurry and Featherfoot).

But, given that very limited description, it could also refer instead to role-based shared skill categories. For instance, let's say there are now 3 or more forms of "Provoke" ("Challenge" (MRD) and "Command" (DRK) join the mix). At level 20, each tank gains a "tank role" ability slot, into which they can insert any of those, without affecting the larger cross-class pool. While this might seem a loss for a DRK or WAR when that tool isn't necessary, or an unnecessary buff to tank toolkits overall, at least that would balance out GLD having to lose an ability just to support the Taunt skill requirements for all three. Each tank learns and makes shareable their particular form of the Taunt skill at the same level, 20.

You might also then see Raging Strikes and Blood for Blood made available to all classes and revised to provide less generic gameplay effects (exchanging a basic "+x% damage over y duration" for something a bit more varied and manipulable in new ways). The same might even be doable with Hawk Eye (making it no longer dependent on Dexterity stat) and Keen Flurry (returning it to an offensive CD-reducer).