Iteration #2:

Many thanks to Killkow for the suggestions on a few needed improvements.

To summarize:

1. Remove a few sub-par sac outlets in favor of cards with more synergy with the theme. Sheoldred, Whispering One for Blood Rites as an example (in addition to adding more creatures)

2. Force my strategy onto my opponent with Hunted Horror, Hunted Dragon, and Hunted Phantasm

3. Add graveyard interaction with Bloodghast and Sepulchral Primordial

Please feel free to add more suggestions below!

For the most part I agree with your assessments of the removal/ addition list. There are a few differences I'd like to point out, though.

• Izzet Signet: If you hit it early game, it's great because it puts you ahead on curve. Late game though, and I agree it's suboptimal. Given that you have so many expensive dudes, I'd say it should prooobably stay in. You're call though. If you hate drawing it ever, cut it. Simple as that.
• Time Warp: I'd leave it in. Worse case scenario, it's like playing 1 less card in your deck, because it just replaces itself and untaps all of your permanents. Best case scenario, it gives you enough time to win the game.
• Rapacious One: 6 mana for... well, not much. If he connects, sure you get sac-fodder. but 6 mana for a 5/4 just feels bad.
• Ashiok, Nightmare Weaver: Depends on your meta. She's honestly better the fewer creatures you expect to face. An early planeswalker on a contained board can be quite strong. If you can't protect her though, it's just a waste of 3 mana and a card.
• Plague Wind: Nah, way too slow for a sweeper. If you realy want expensive board wipes, consider In Garruk's Wake (which I still don't love), or Decree of Pain (which I'm a large fan of)
• Rise of the Dark Realms: Homestly, I don't care for the card. I haven't used it personally, but I've never been impressed when an opponent casts it. In our meta, graveyards are usually controlled fairly well, and there are typically much better things to do with 9 mana. Then again, the decks I run aim to put the game away with just a couple of creatures, so it's hard to keep my board clear, since I don't overextend when I don't have to.
• Prince of Thralls: I don't think it does enough for its cost by the time he comes out. At 8 mana, most of the durdly creatures have already been sweeped, and the bigger creatures can probably deal with prince before he has much affect. Also, the 3 life is super negligible.
• Insurrection: I'm a fan of the card. It's dead in the hand A LOT, make no mistake. However, if you find an opening, it's usually just "8 mana win the game." Might not be as good in this deck, since your plan is "No creatures for my opponent ever", though.Depends on how resilient your opponents are to your strategy.
• Nekusar, the Mindrazer: Nah. Doesn't fit well with your strategy. He's just for all-in Nekusar decks.
• Cyclonic Rift: Literally the best staple in EDH with access to blue. Put it in immediately.
• Pithing Needle: Only if your meta calls for it. Are there particular commanders in your group with activated abilities you just can't beat?
• Sphinx of the Final Word: If your opponents play Counterspells, put him in. He's pretty great. Also consider Teferi, Mage of Zhalfir for more of the same effect (if needed).
• Chandra, Flamecaller: Meh? I haven't seen her in play, and she may fit with your theme. Might be worth some playtesting.

Additionally, I'd consider these:

• Bloodgift Demon: I'm a pretty big fan of him. I think he's much better than Indulgent Tormentor at the very least.
• Ob Nixilis Reignited: This card has proven to be sweet. Does everything you want a P'walker to do. Protect himself, gain card advantage, and provide an ultimate that can win you the game.
• Dissipate/Void Shatter: With the change to the commander-tuck rule, I'd say the exiler's are better than the bottom of library counters.
• Crux of Fate: Unless you encounter both frequent dragons & non dragons from your opponents, it's a very respectable sweeper. There's even the lovely niche scenario where you get to keep a Ruthless Deathfang, or Hunted Dragon through the wipe.

Also, keep in mind that with Crypt Rats you have to pay black mana only into him. That can be quite the chore for a 3 color deck, even with Urborg, Tomb of Yawgmoth. It's the same reason that Cabal Coffers is sketchy in 3 color anything, too. Not saying don't use them. Just keep it in mind, and pay attention to how frequently they operate sub-optimally.
Hope this helps!