There are no cards in Wastes that are particularly grueling. They all just work so well together though. I played over a dozen times with 3 wins and the last win being very clean. It's a great quest actually and so far cycle 5 is my favorite but it is so long and you have to get such lucky draws through setup and all three phases, I don't see myself revisiting it too much.
Used classic spirit and tactics in 2 monosphere decks. Aragorn, Mablung, Hama and Eowyn, Glorfindel, Galadriel.
This combo basically just engages and locks down everything and quests like crazy. The reason the win rate was so low was I couldn't draw test of will to save my life. These decks have beat Chetwood, Dike, and now Wastes
The key cards are
Fient
Thicket of Spears
Hammerstroke
Westfield Outrider
Knight of Minas Tirith
Tireless Hunters
Daggers and Spears to fuel Foe Hammer and Straight Shot
Other side is pretty standard heavy questers plus
Test of Will
Hasty Stroke
Counsels and Greetings for threat
Light of Valinor
Unexpected Courage
Ancient Mathom
Trackers
Nenya for Healers and Asfaloth
Both decks also have one copy of the Gather Info side quest as it can keep the Shrouded Hills from surging and make Pressing Needs less painless. I don't recommend ever trying to progress on anything but the main quest though as every daylight round progress is precious. They are good to play if Weight of Responsibility is already discarded and/or you have A Test of Will in hand.
I do not believe this quest is beatable without some way to engage the Pack Leader through card effect or deal direct damage or attack the staging area as Day Time will continuously remove the progress and make him damage immune and Night Time will stop progress. Basically it is possible to build a deck that can't possibly beat this scenario. Anyway on to Jailbreak and then maybe Nightmare.
Edited by midwestborn86