I’m wondering if things haven’t moved on since the last time I pulled Thraximundar out of my binder.  I sat down for a few games with the deck last night, and left with a pretty cold and underwhelming feeling. 
Before I go any further, here’s the list I sleeved up:

General: Thraximundar

Butcher of Malakir
Consecrated Sphinx
Deathbringer Thoctar
Evil Twin
Fleshbag Marauder
Gatekeeper of Malakir
Harvester of Souls
Ingot Chewer
It That Betrays
Lazav, Dimir Mastermind
Notion Thief
Phyrexian Delver
Phyrexian Metamorph
Prince of Thralls
Puppeteer Clique
Reaper From The Abyss
Rune-Scarred Demon
Sepulchral Primordial
Sheoldred, Whispering One
Slum Reaper
Solemn Simulacrum
Steel Hellkite
Trinket Mage
Tyrant of Discord

Armillary Sphere
Beacon Of Unrest
Beseech The Queen
Black market
Cauldron Dance
Chainer’s Edict
Coalition Relic
Consuming Vapors
Cruel Ultimatum
Darksteel Ingot
Decree of Pain
Diabolic Edict
Diabolic Revelation
Fact Or Fiction
Geth’s Edict
Grab the Reins
Grave Betrayal
Grave Exchange
Grave Pact
Nihil Spellbomb
Oblivion Stone
Phyrexian Arena
Phyrexian Reclamation
Plague Wind
Promise Of Power
Rhystic Study
Sensei’s Divining Top
Slave Of Bolas
Sol Ring
Spinal Embrace
Syphon Mind
Thran Dynamo
Twisted Justice
Wild Ricochet
Word Of Seizing

High Market
Blood Crypt
Bojuka Bog
Crumbling Necropolis
Dragonskull Summit
Drowned Catacombs
Evolving Wilds
Minamo, School at Water’s Edge
Miren, the Moaning Well
Mystifying Maze
Reflecting Pool
Shinka, The Blood-soaked Keep
Shizo, Death’s Storehouse
Steam Vents
Strip Mine
Temple of the False God
Terramorphic Expanse
Thespian’s Stage
Tolaria West
Watery Grave
Winding Canyons
5x Island
5x Swamp
5x Mountain

I came to this list basically exactly how I had threatened to; I took the original good-stuffy Thraximundar list I had been running back in the day that spawned my original project, and I cherry-picked from both Imshan and Patrick’s suggestions to come up with a “sacrifice matters” list that is obsolete by at least one solid year.
Yeah…I doubt I’m surprising anyone with the direction this is going.
From there, I shuffled it up, goldfished it, analyzed it a bit further, and then added in some new stuff that seemed to be a decent fit for the deck; with all the creatures dying, Lazav seemed like good value, for example.  Evil Twin picked up a decent bit of utility with the new M14 legendary rules changes, so in he went.  Sepulchral Primordial is getting another try after the fiasco that I experienced the first time I played it, and Notion Thief seemed like a solid combo platter of card draw and resource denial.
There are some gaping holes, primarily in the mana base.  I don’t readily have the Revised duals and correct fetchlands to make this tick, and I wasn’t about to invest that much money in an unproven (read: could get taken apart in anger at any time) build. 
Ironically, this actually played a large role in making the first game I played with the deck suck.  Grixis is probably the worst color combination for mana acceleration and fixing, having to rely nearly totally on mana rocks to get the job done.  Not having fetchlands to smooth out my available mana meant that I spent a decent chunk of the initial game staring at a hand full of double-black costs that I couldn’t touch.
(Of course, another part of the problem is that I also jammed the deck with six-plus mana double and triple-black costed creatures and spells.  I can almost put my finger on the problem here…so close…)
Anyway, the deck itself seems to do what it should (barring mana fixing issues.)   I found land drops, had draw and tutors at the right time for the right things, and Thraximundar was fairly easy to bring to bear. 
The real problem as I see it is the reliance on sacrifice.  Sure, it plays nicely with the theme, but spot removal is usually underwhelming as it is when faced with a typical game.  When you suddenly flip the script and make that spot removal more of a suggestion than a definitive answer, you end up in trouble.  I had plenty of occasions where I was staring at Diabolic Edict and an opponent with a creature I really wanted to kill and a totally inconsequential creature that was clearly ear-marked for getting the axe.  Frustrating.
The other overarching issue is that, as I intimated above, I really think EDH has evolved from the last time I played this deck.  My metagame is rife with tokens decks and green ramp decks, both of which do a great job of outpacing my removal here.  The end result is that I sit back on a hand that I can’t leverage, someone picks off Thraximundar, and I’m dead in the water.  This happened multiple times, and I spent a good portion of both mid-games twiddling my thumbs while the other players made big moves on their turns, only to get to mine, draw something inconsequential, play a land and pass.
Honestly, the best thing it did (and this was pretty cool) was to Evoke a Slithermuse, targeting Mr P with the trigger.  Mr P was playing his Ruhan coin-flip deck, and had been allowed to keep Mind Unbound and ReliquaryTower in play for several turns.  That equated to drawing roughly fourteen cards.  And about another fourteen a few turns later when I resolved Cauldron Dance to get it back.  Somehow, the card quality meant this did not matter in the long run; by the time I was eliminated form the game, I had a tapped Thraximundar and a handful of sub-par spot removal. 
(Meanwhile, Mr P was busy leveling up a Goblin Bomb for the win…)
Clearly, this thing needs an overhaul already.  I really like Thraximundar as a general; there’s something awesome about fearlessly swinging into a board with a single Blightsteel Colossus or Ulamog that makes him very appealing.  I do know that this build will cause me to tire out in a hurry if I can’t come up with a decent way to save it.
Zombies.  Tribal Zombies could still work, I suppose.  I’m trying to steer clear of that sort of thing, though, because it might as well just be Sedris, the Traitor King for  raw functionality or Lord of Tresserhorn for flavor and old-school cred.  For what it’s worth, Thrax might as well not be a zombie at all for all the flavor and artwork he comes packaged with.
Role-Player.  I could bag the “sacrifice matters” theme and just build another one of my famous “Playing all the time”-style decks.  Despite my usual dislike for the red/black and blue/black color combinations, some of my all-time favorite instants reside there – Memory Plunder, Spinal Embrace, and Cauldron Dance among them.  I could take this thing, pull out the under-performing sacrifice spells and supporting creatures, and instead tune this to be a monster board controller that can leverage Thrax as a solid win-condition.  If it takes this slightly-more Voltron-ish direction, I can also work a bit more on protecting him too. 
On the plus side, I love decks like this.  On the minus side, I need another one like I need a hole in the head.  There’s a slight concern that several of my decks are just different-colored versions of each-other, and I don’t necessarily want to add fuel to that fire.
Still, I really like this style of deck.  Maybe I just need to get over myself and play whatever feels good…
Stay The Course.  There has to be a way to make this work, right? 
So I guess this is a bit of a call for help.  What’s the right direction here?  Should I take this thing in a different direction, or are there some obvious things (the crappy manabase, glut of expensive creatures, and ineffective removal choices, for example) that I could change to make the deck better?  
I’ll take any help I can get here, folks.

At least Kresh is around the corner.  This thing is shaping up to be a monstrosity, and I’m excited to see if I can tame it. 
I also have some discussion to open up surrounding my Omnath “alternative win-con” deck.  And there’s the results of the “What do EDH players want?” questionnaire to put on the table. 
So much to do…