I think I'd just run 8 removal spells rather than a 2 card combo to push one of 4 spells through. Your odds of drawing 2 removal out of 8, even with 1 being countered, is greater than you drawing a cavern and a wisp. It'll really suck when you cavern a wisp and they mindbreak trap it :p.
This is an interesting unorthodox idea. Do we have a critical mass of Elementals we can easily cast for one, maximum two mana? Other than Wispmare and Ingot Chewer, there are only a few others that I see can be useful - Shriekmaw and Flamekin Harbinger. (There is also Spark Elemental that can make zombie tokens, but this is a different approach you tried already with Shifting Wall and Walking Ballista. And since we are talking about fighting Leyline of the void, making tockens strategy doesn't work any way.)
So it looks like if we want to use Cavern of Souls, we lock ourselves in a scenario "wispmare or bust." And this is assuming that we already have Cavern. And since we expect to face Leyline, we can't really maximize our chances of getting Cavern with help of Petrified Field. So, kind of the entire structure falls apart.
On a different note, but similar in spirit, why then not to use Reverent Silence with several Bayous and Tropical Islands? This way we can have more "disenchant" or "boomerang" effects than they counterspells. Just an impromptu idea.
Yes it's Wispmare or bust, but most Dredge decks are only playing 4-5 answers to enchantments and 6 mana sources right now. I don't see how we're that much worse off going for something like this
Since you mentioned it, the 0/0 plan is/was pretty good, but it depends on the hate being played mostly being Cage/Priest, which is not really true at the moment
I'm looking at this list now:
4 Bazaar of Baghdad
4 Serum Powder
4 Golgari Grave-Troll
4 Stinkweed Imp
3 Golgari Thug
1 Prized Amalgam
4 Cabal Therapy
4 Bridge from Below
4 Force of Will
3 Mindbreak Trap
4 Mental Misstep
2 Leyline of Sanctity
1 Leyline of the Void
1 Vengeful Pharaoh
1 Bojuka Bog
1 Chalice of the Void
4 Petrified Field
4 Cavern of Souls
2 Mana Confluence
2 Flamekin Harbinger
2 Ingot Chewer
The idea vs Containment Priest would be to Unmask it, Force it, beat before it can be played, or simply dodge the opponent drawing it at all.
The idea of the Mountain is that vs artifacts you want to blow up Wasteland is a big factor and typically your graveyard is active so you can Petrified Field for it. On the other hand, vs Enchantments your graveyard is not active and Wasteland is not as big a factor.
Edit: Changed 1 Ichorid to 1 Prized Amalgam to up the blue count. Changed 2 Unclaimed Territory to 2 Mana Confluence to be able to cast Cabal Therapy. These could be any rainbow land and I don't know which.
Its an okay board plan for a Manaless Dredge deck. Having uncouterable answers to hate is great. On the other hand, having to guess exactly what hate pieces your opponent is playing is not great.
Just a note on one of the comments, dismember is also a poor answer against Lavinia because you need 3 lands in play to cast it. Reality is if your opponent casts both Lavinia and Contaiment Priest before you do anything, it was a pretty rough game. Spinning Darkness is superior as it only takes 1 card to remove the Priest, not 2 that dismember requires.
Agreed, re:Lavinia / Containment Priest, but I'm not sure if that's an argument for running Spinning Darkness or for running no creature removal.
Regarding guessing what anti-hate to bring in, there is some decent separation by archetype at the moment. Xerox is pretty heavy on Leylines, Oath can't run Cage, and so forth. Additionally, Flamekin Harbinger helps mitigate the split somewhat by fetching whatever they happen to have.
I've seen a certain World Champion Dredge player try this board configuration before with the Harbinger, and to say the least he didn't keep running the deck very long. Its too much set up just to kill 1 anti-hate piece. The format is so much faster now since I've seen that list too. I think you just have to take the gamble with a SB like this and hope that your opponent doesn't pull out something unexpected.
Muldrotha is definitely playable, but not really in these lists. There is a really nice infinite loop with it, lotus and animate dead that allows you to recur all your non-land permanents if I can ever make it to a paper event (or MODO actually learns how to fix the no looping issue).
I have a really hard time imagining that a modern pitch list which runs only 5-6 removals for Leyline is just fine but if you make most of those removal uncounterable at the cost of being slower a portion of the time, that this is a horribly losing proposition.
Like, compared to that list mine (several posts above) is lacking Hollow One and Dread Return, but packs a bit more disruption and has a very comparable anti-hate package that usually can't be countered. I can see how that would be similar, I can see how mine might be slightly worse, or I can see how mine would be way better. I really don't think mine could be way worse though, because it's the same core strategy with a very similar deck post-board.
Is it possible that Mark's deck was bad for reasons other than the Cavern of Souls package? When you're playing a faster build of Dredge it hurts a lot to run into any hate because your opponent got to operate with little or no disruption and you have to use those speed elements to catch up once you've cleared the path. With more disruption you're not necessarily behind in the first place
Mark's list was fairly stock, at the time, outside of the sideboard if I remember correctly (that is to say it was some variant of Always Sunny Dredge). This was all prior to you and I developing the transformational board though since I recall I was playing a very early iteration of my creature transformations (aka bad BUG fish). So it was quite a few years ago. Its possible that the meta has shifted to make this more playable, but seems unlikely to me as the format was super slow comparatively, which is why my plan, at the time, of Dryad Arbors + casting stuff like Golgari Thugs could get there in game 2/3s.