Diablo III Barbarian and Witch Doctor Skills Detailed

Diii.net continues to round up everything we know about the character skills in Diablo III thus far, with the Barbarian and Witch Doctor falling under their microscope this time around. Spirit Walk sounds like it might have some potential:
Spirit Walk
Rank: 0/5
Description: Enter the spirit realm, allowing unhindered movement for 3 seconds.
Mana Cost: 12

***Not Yet Implemented***

An interesting skill. It's not clear just how this works; can the Necromancer essentially teleport, moving through monsters and walls and over ledges? Or is this just a sort of (pass through enemies) ability, that lets him escape mobs of monsters, but not move anywhere he could not normally walk to in that same amount of time? Note that nothing is said about minions, so presumably this one works only for the Witch Doctor, and his Zombie Dogs and other servants are on their own.

Since it was another of the NYIs, there was no way to test it, or see what sort of gain more points would yield. It seems like the duration of the time in the spirit realm would be increased. If the time could be increased significantly, it might become useful for item runs, or fast, safe movement through dangerous dungeons.