Continuing to look at the new Psychic Disciplines, I am sure there will be lots of new gameplay potential for SWs, which is quite exciting. That said, we already know one power: VEIL OF TIME — 2 Warp Charges, Blessing, allows targeted unit to re-roll all failed saving throws.
Combine this with a Wyrdstorm Brotherhood and a TH/SS Wulfen pack and you can have a very survivable unit, since the Wulfen would have a re-rollable 3++ (that is an 88% chance of passing their saving throw, and since it is an Invul Save, it cannot be ignore by anything besides D Weapons and certain very rare items like the Callidus Assassin’s C’tan Blade).
Doing the Mathhammer, it would take the following to kill a SINGLE Thunder Hammer/Storm Shield Wulfen with Veil of Time cast:
-81 x BS4 Bolter shots
-48 x BS4 Plasma Gun or Scatter Laser shots
-54 x BS4 Grav Cannon/Amp shots
-43 x BS3 High-Yield Missile Pod shots
-48 x BS4 Scatter Laser Shots
-16 x BS4 Lascannon or Meltagun or Railgun shots
-21 x WS4 S8 Power Fist attacks
-72 x WS4 S4 CCW attacks
So, the only thing left is ensuring that you can successfully cast Veil of Time each turn and getting the Wulfen across the board fast enough to catch your enemies.
The mobility issue is somewhat mitigated by Wulfen’s Bounding Lope, but you probably still need a transport, method of Infiltration (i.e. allied Lias Issadon), building Escape Hatch “slingshot,” or some other way to increase their mobility to reliably get the Wulfen stuck in and make use of the uber killy-ness and the survivability described above.