This is essentially a correction article which I have linked below for reference/interest/entertainment as you see fit!
Most of the articles I do that cover decks are on specific lists I have recently built or archetypes I have decent experience with. Some of the more exotic combo, tribal and block mechanic based ones however are often plans. I use them to design a list which I will later build and test. Mostly these are fairly close to the mark and I only change up a couple of cards once I have actually played it. Well, when I came to build up my Ascendancy combo deck I learned quite how badly I missed the mark. The deck was horrible, practically unable to win. As Ascendancy is an engine deck effectively just getting a couple of cards wrong wrecks the deck and I got more than a couple of things wrong!
Birds of Paradise
Reason / Believe
Slight of Hand
Emrakul, the Eons Torn
One of the main concerns with this combo is fizzling. That is pretty easy to do and the more things that you play which don't draw you cards the more likely that is to happen. This list is only a third cantrip cards which is still cutting it fine. That meant cutting all the fluff like Path to Exile from the old version. One of the biggest cockups on my last list was me simply not realizing how Retraction Helix works, I thought it was an aura and that you could bounce it repeatedly and even tutor it up with Enlightened. Well, it does none of that... You could slap an Abundant Growth in the list which would allow that to work and otherwise be a fine card in the deck but with no ability to tutor up the Helix and it being pretty useless until you are in the full swings of going off I just abandoned that game plan.
Another card that utterly failed to do the intended job I had for it in the previous list was Gaea's Blessing. I had no way of milling it into the bin and as such no way of getting that reshuffle, a mere 3 cards from casting it normally isn't buying you the time you need from such things. After a little bit of time weighing up the options I went with the Emrakul plan. I have loads of ways of discarding it when it is dead or I need the library refill, it allows me to sensibly run Reason / Believe, and most relevantly you can just combo off into casting Emrakul should they have some blockers down to halt your attacks.
Other cuts were Visions of Beyond, basically if you get to 20 cards in your bin you have probably won. I think a Whisper's of the Muse would be more use! Mostly both will just cycle for one. Cruise is far far better (obviously) only needing 7 cards in your bin and giving you control over what cards stand to get reshuffled back into your deck.
Frantic Search and Faithless Looting are not ideal in that they don't replace themselves and will contribute to you fizzling. They do however dig deep and provide other good utility. Frantic is lovely mana generation and Faithless is a good use of red mana (which you wind up having some excess of) and also a spell trigger you can use from the graveyard.
Noxious Revival is so so, it gives some mild protection to having your Ascendancy put in the bin but mostly I found it was a way to generate mana when going off quickly. Essentially you get back your best draw spell and discard a card to get an untap and dig a bit deeper. Due to the way the Ascendancy stacks you do need to follow it with another non-creature spell to get the thing you put on top but it doesn't have to be a draw spell also thanks to the Ascendancy. All this ends up making Revival like another Frantic Search or Faithless Looting but with a bit more utility.
Fatestitcher is easily your best mana dork as it comes with haste, only costs one, usually generates all the colours of mana and doesn't even cost you a card in hand to get online. Bloom Tender is obviously a huge upgrade on Rattleclaw Mystic which I totally missed. Thanks to a reader for suggesting that one. Going off with Bloom Tender makes it super easy to cast an Emrakul. Arbor Elf is the weakest of the mana dorks even with the perfect mana base. You cannot cast the turn two Ascendancy with it and without a forest that taps for blue the thing is super unhelpful in trying to go off.
More cantrips with card quality effects and one less land also help reduce the chances you fizzle. So, sorry to anyone who had a stab at this deck using my last list as a guide. I suspect you got hammered pretty hard! I shall try and do a better job of stating if I have played with a deck or if it is an idea I plan to do in future.