The latest MTGO results came back and have some showings for Jund Death's Shadow. They vindicated my main change of adding Murderous Rider as a tutorable spot removal spell, although I find Bonecrusher Giant to be a questionable tutor target. Another Jund DS list has Once Upon a Time instead of Manamorphose, which definitely looks cool in this land-light deck and can help this dodge graveyard hate on Traverse the Ulvenwald (although costing 2 mana on its plentiful off days might bite).
Probably quite good and easy to enable in this deck because turbo Delirium hands often already make it a 4/4 (Bauble is 0, Street Wraith is 3BB, targeted discard is B, Traverse the Ulvenwald is G), yet it's so darn vulnerable to early graveyard hate that I'm not sure I should make room for it, especially when I'm still on Wrenn and Six. A fatty with Flying would be pretty dandy in this deck, though...hmmmm....
I'll maintain that Force of Despair and Wrenn and Six are the only remotely playable cards for JDS out of this whole set so far. And those are likely Sideboard at best
I've tested Wrenn and Six in JDS, and from my testing results, I think Wrenn and Six is actually maindeckable.
While Crucible of Worlds: The Planeswalker doesn't intuitively seem that good, what pushes her to playability in JDS where she failed in Jund (at least in my testing) is her ability to accelerate out Death's Shadow by recurring painful fetchlands. Also helping are JDS's low curve (to the point where supporting 3-drops can be a stretch), desire to hardcast Street Wraith (oh man, before Wrenn and Six, I've wished I could hardcast Street Wraith so many times), and greater need to deal with go-wide strategies that love X/1's.
When not hardcasting Street Wraith, having enough mana to regularly Traverse the Ulvenwald for a threat and play the threat in the same turn feels swell. Even better: playing 2 Traverses and 2 threats in the same turn!
Her ult pretty much always enables a kill in 1-3 turns, regardless of whether she lives post-ult, and you'd be surprised how often you can kill the turn you ult her. She takes almost too long a time to ult, though.
I traded out a fetchland for Nurturing Peatland to try to make Wrenn and Six a little better, and I don't regret it at all. It incurs pain early-game, and it pops for a card by the time your life total gets too low. Its turning Wrenn into a full draw engine feels great, but I've never tutored for it with Traverse.