Sultai Graveyard (Modified for Arena bo1) (Standard)

Trying to adapt a few different traditional standard decks I've seen online in order to make a solid bo1 deck. The bo1 meta is all over the place right now. There are many strong decks that all do very different things, therefore it is really hard to nail down a deck that can compete with the speed of RDW abd White lifegain, go toe to toe with midrange decks like Grixis, have power enough to hang in there with Simic Ramp, and also have a gameplan against Dream Trawler. Truth is you aren't going to build a deck that has a good matchup against everything. Your best hope is to play control, but then you are playing very long games (sort of against the point of bo1).

My thinking is ramp gives you the most powerful threats imaginable. My issue has been that Simic Ramp has very few ways to answer the opponent. I feel modifying the Sultai builds floating around is the way to go.

The core of the deck remains the same no matter what:

1) Arboreal Grazer (you want turn 1 ramp)
2) Paradise Druid (backup plan)
3) Uro (great ramp piece, excellent turn two play, a bonus card, and 3 life to survive against aggro)
4) Rotting Regisaur (also a fine turn 2 play that draws attention, it is ok to discard escape cards)
5) Polukranos (big body, decent removal piece, nasty when escaped)
6) Tamiyo (gets back any card, oh my goodness. Gravefill also very relevant.)
7) Cavalier of Thorns (big body that blocks flyers, Dream Trawler, gravefill, ramp, return a card)
8) Nissa (formats best card, we can play it by turn three, it stills takes over a lot of games)
9) Hydroid Krasis (the comeback kid. Survive and reload).

Now for the flex slots:

10) The Great Henge-
lifegain is very important
also serves as amjor ramp
free card draw
Regisaur makes this silly

11) Casulties of War-
a minimun two for one, often a three for one.
great in a format with so many powerful enchantments and Banishing Light.
lots of planeswalkers to target.
in ramp mirrors it swings the game so fast.
Enchantment creatures give it extra targets in mono-colored decks.
*weaker against aggro.

Other options I considered:

a) Agent of Treachery
*I've played this in the top end slot a lot, it is nasty and induces a lot of scoops.

b) Kiora Bests the Sea God
*very powerful, but feels slow some games I've played with it.

Looking at some card numbers:

a) I'm only playing two Hydroid Krasis. This could change, but I like a lot of the other top end options as well. Something could be cut to make room for another copy.

b) x4 Arboreal Grazer. I really want to get Regisaur on turn 2 or Nissa turn three whenever possible. Grazer makes this happen.

c) x4 Nissa. Some people online are playing three, but i just don't see a situation where I don't play a 4 of the best card in the format in the archetype it excels in.

d) x2 Polukranos. I haven't played with it yet so I'm starting out with two. It looks insanely powerful and may need to be a three of, but I cut one to make a spot for Casualties of War.

e) The mana base. I'm playing more lands that enter untapped then many lists. Fabled Passage looks strong here as early it is ok to enter tapped if it enters off a Grazer or Uro. Late you want lands that don't enter tapped to go off as big as possible.

Issues for the deck:

a) Aggro. Pure aggro can kill us before we stabilize.

b) Not a lot of answers for Dream Trawler.

c) Removal is limited.