So I think the deck is both stronger and weaker than I thought.
The lategame is pretty amazing. You have so many different win conditions that I can see why you dropped the 2nd runescarred demon. The mana works better than I expected... all hail our triland overlords.
On the other hand, there are some serious weaknesses. Most of these are a direct outgrowth of running a 5 color seance deck with a bajillion combos.
- Slow manabase. Not being able to cast your 2 drop until the 3rd turn is a very common occurrence. The trilands are doing their jobs but they slow the deck down significantly.
- awkward transition between chumps and bombs. The deck goes from 1/1, 0/2, 0/4 at 1-2 mana straight to five drops (and most of the 5 drops have weak board presence for their cost). When combined with all of the taplands, it can feel like an eternity before you get to your late game. Obviously very limited control options due to this being a seance deck.
- Too many "do nothing" combo cards. Lets see:
4 cloudshift
3 hedron crabs
2 warstorm surge
3 warden / 3 oracle
1 craterhoof behemoth
That is 16 cards. This is kind of an arbitrary selection, there are cards I arguably should be listing and cards I arguably should exclude. My point is that you have many cards with very minimal board impact. If your deck is working on all cylinders and you cast turn 5 seance turn 6 warstorm surge it doesn't matter. But drawing cards in the wrong ratio can hurt.
So I would want to try to refine the deck in one of two ways:
1. Focus on getting to the late game faster. Cultivate can speed you up two turns by ramping + guaranteeing an untapped land in your hand for crucial turns. You might also be able to get away with swapping two trilands for two basics, the net result would be significantly speeding up your deck. I would cut 3 visionaries/walls and 1 cloudshift. Cantrip creatures are nice for a deck with fewer win conditions to have a way to draw into them. They fetch you less than half a land on average. This isn't a deck where you want to stall at 4-5 mana. The synergy with seance is nice but satyr wayfinders are the prime seance creature here.
Ramp may add more functionality to cloudshift. As it is, I can't use it to save my big guys from removal because I need to cast them ASAP. As you mentioned, cloudshifting oracle is incredible, but it is difficult because of the heavy curve with no ramp and tons of taplands. If you are ahead on land drops (and have untapped lands for key plays) you can afford to do something like cast rune scarred with one mana open and then shift him in response to removal. Just for reference I played a decent amount with Eon's 4 color blackless shiftwarden deck that used warstorm surge. He had less EtB abilities but more big guys that I wanted to stick on the board. Keeping something like
Wooly Thoctar or
Garruk's Packleader alive is a great use of cloudshift, using it as a cantrip is not so worthwhile.
2. Add more board presence lower on the curve. There are a lot of options here... lone missionary could be good, as could guard gomozoa, as could more spider spawnings. Again you have so many powerful late game cards that the early game cantrips aren't super necessary. Pellaka wurm doesn't feel super good without ramp here, I would rather have some lifegain lower on the curve. Its amazing with seance but then again so is everything.
This is based on pretty limited testing at this point. Very fun deck and I think it is viable for the steam meta.
This is part of the reason why my ShiftWarden deck went the way it did. Running a bunch of cards like Wall of Omens and Elvish Visionary felt a bit too benign. I certainly see the point, as the cantrip creatures do a good job of cycling you into your combo pieces, which can be very beneficial for getting yourself set up and they work decently well with Cloudshift.
The problem was AFTER we had gotten things set up though. Cards like Wall of Omens and Elvish Visionary do a very good job in getting you to combo pieces like Warstorm Surge and Warden. Once you grab the combo pieces though these cards tend to take a serious hit in the value department. Once you have Surge on the table, you really don't want to be drawing into cards like Wall and Visionary, because they really don't do much for you in terms of the combo itself (Wall does 0 damage with Surge for example).
Admittedly the cantrip effect can help you cycle into more cards that actually DO function with your combo, which is nice, but consider that the more of these cantrip cards we run, the more likely we are to hit multiples (potentially off of the draw from the initial cantrip). This certainly helps to thin the deck out, but it also has the potential to slow the deck down quite a bit due to mana economy.
Lets say we have Surge on the table and draw into Wall of Omens. We cast Wall (which doesn't do anything with Surge) and cycle into Inferno Titan. This certainly isn't a bad line, but consider that if we would have just drawn into Inferno Titan (or other similarly sized bomb for Surge) to begin with we would be able to start applying pressure sooner, especially when you take into account the fact that after casting that Wall, we may not have the mana remaining available to cast that Inferno Titan (or whatever) on the same turn we cycle into it.
Hence why I went the way of things like Thoctar in my build, which are sizable threats when played early and/or without having your combo pieces available, which also happen to be sizable threats in the late game that greatly speed up the clock when you DO have your combo pieces.
Now in saying this, I will say that these cantrip creatures certainly do have more value with Seance around, and the idea of Surge+Seance is definitely an interesting concept I had yet to even consider. Good on you Auunj! This may be something I mess around with myself.