With the release of WAR, we got a whole new Genre of Planeswalker. The typical Mediocre +1/2, Impactful -(2-4), Game-ending -(6-9) model has been abandoned.
Many new walkers have been pushed precisely because they don't have that "answer me or lose" ult. The static abilities are also incredibly powerful. The typical issue of walkers in muldrotha, the often-awkward numbers involved in killing themselves made them rarely worth it.
I've been testing with 4 of the new walkers. I doubt they will all make the cut at the end of the day, but I'll lay out what I'm testing, what I cut for it, and why.
Karn, the Great Creator: Another Null Rod is great, particularly because we can actually combo through this one! He can also buy back the LED, meaning we now have redundancy against all 3 pieces being exiled! (Anim/Necro, Phant/Dance, LED/Karn). Popping moxen and crypts is also really fun, and his absurdly high loyalty means he might survive a turn cycle before we deploy something to protect him.
Ashiok, Dream Render: Search hate is great, repeatable grave hate is a nice bonus, and, we can target ourselves with the -1 to fuel the bin. Hybrid cost makes Ashiok easy to recast without taking us off colours we need for interaction.
Narset, Parter of Veils: I mean.... screw Tymna, right? Add that to a double Impulse and low CMC, she cements our card advantage off of Muldrotha in the long game, and really makes opponents lives difficult in the short term. UU is a pretty serious downside, as this deck has pretty diverse colour requirements, so it might be a struggle to card her and hold a counterspell, for example.
Tamiyo, Collector of Tales: Whew lad. This card does everything we want for this deck. The +1 is situation card advantage, particularly with some sort of Topdeck manipulation. It fuels the yard even if you whiff. The -3 is beautiful. It lets us buy back all the non-permanents we milled, and along with the starting loyalty of 5, the +1, -3, -3 to cycle her means we can actually be buying back a non-permanent card every turn. Her passive is easily the worst of the 4, but you will definitely catch someone out when they cast a Wheel without reading her fully. Her cost is very high and she has no real immediate impact, but in grindier, controlier metas, I'd consider actively tutoring for her.
Other Changes: Blast Zone is replacing Scavenger Grounds as we want to be able to answer Breakfast without crippling ourselves.
Things that aren't going in: Kaya's Ghostform. While this card opens up a whole new realm of possibilities for the combo (including Food Chain), we don't run sac outlets, and the list would need so many changes to move towards a sac-outlet oriented build. I may work in this as an alternate build, but for now, no Ghostform.
Cuts:
I haven't decided what will be coming out and what will be staying, so I'll provide a summary of some of my considerations
Expedition Map: This one comes in and out as a Meta call. Sometimes it's literally worth tutoring to find Cavern of Souls, then Command Beacon and with all the tech lands (and expecially the new Blast Zone)
Glen Elendra Archmage: This card is really slow, and doesn't function as the double Negate you might wish for when comboing, because people can respond to the persist trigger. While it has won me games, it has also sat in my hand a LOT.
Sinister Concoction: The requirements are just a little too steep for what it does, particularly the discard hurts.
Mindslicer: I've actually been using this a lot recently, I seem to frequently draw Slicer or Tower, and then tutoring for the other half is very easy. I've found it doesn't actually win me that game nearly as often as I might hope, particularly when Tymna players can easily be drawing 3 cards a cycle.
Bitter Ordeal: The non-infinite Bitter Ordeals are cute and infrequent, and the addition of Karn means that I can get back the ballista from exile, and recurring Ashiok also lets us exile libraries to win.
Life / Death: I'm too cowardly for "miminum resource" Razaketh Lines, particularly with no Pact of Negation in the deck, so I rarely use the Life half, and "bad reanimate" is not a card I want in this "not reanimator" deck.
Nezahal, Primal Tide: I don't know what it is about this card, but I seem to not-infrequently lose with this guy in play and 12+ cards in hand. Maybe it's the way I pilot or I am too aggressive about casting him with little mana held up, but it's not working for me. YMMV
