I think the Champions of Fenris Greatpack is quite intriguing, especially with its new version of Logan’s “High King” rule:
1 – All units gets Fearless
2 – WG, TDAWG, and TWC get +1WS
3 – All units from this Greatpack within 12″ of Logan get one of the following rules each turn (you choose): Tank Hunters, Monster Hunters, Preferred Enemy, Relentless, or Furious Charge
With the new “High King” 12″ bubble (which can be extended even further by putting Logan on his sled ), you basically are getting an improved version of the infamous Tau Puretide Engram Chip which affects multiple units at once, instead of just the bearer and his unit.
There are tons of possible applications, but here are some that jump to my mind right out the gate:
1 – Logan Drop Pods in with multiple Plasma Grey Hunter Packs and uses Preferred Enemy to buff all their S7 AP2 Rapid Fire goodness.
2 – Logan rides his Chariot in the middle of multiple maxed out Blood Claw Packs (along with some nearby Wulfen to amp up their abilities even more) and grants them Furious Charge.
3 – Logan rides in his Chariot with multiple meched up Long Fang Packs and grants them Relentless so they can shoot from the hatches of their Rhinos or dismount from their Razorbacks at full BS even after moving.
4 – Logan rides in his Chariot along with multiple TWC packs, granting them either Preferred Enemy (general use), Tank Hunters (assaulting enemy mech), Monster Hunters (for tearing down Tau Riptides and Eldar Wraithknights in close combat), or Furious Charge (for S6 attacks on the charge against T3 enemy like Eldar and Tau).
As you can see, there are many uses for Logan and his Greatpack formation. I think the biggest drawback is the high minimum unit requirement to make this work (i.e. Logan, 2 WG/TDAWG/TWC Packs, 3 Blood Claw variant Packs, 4 Grey Hunter Packs/Land Speeders, 2 Long Fang Packs MINIMUM, which is going to be most of your points right out the gate).
Still, I think the Champions of Fenris Greatpack will make for a competitive, fun, and fluffy option for Space Wolf players. I think this would work particularly well, if you can spare enough points, in conjunction with an allied BA Lucifer Armoured Task Force, which can put multiple armored units (with lots of Flamestorm cannons) up in the enemy’s face before the game even begins, thanks to Scout moves, thus taking target priority away from Logan (who is the lynchpin of this force) and all the Space Wolves escorting him.