Lands:

I think you can do away with Cabal Coffers. It doesn't help you much if you're in a rush to win since it requires Urborg, Tomb of Yawgmoth and at least two more lands to ramp. You might be better off using Land Tax to ensure you never miss land drops. It can also help you pay for Forbid's (you can run this in place of Dessertion or Cryptic Command) buyback cost. This also eliminates the need for Vesuva.

I'd also lose the temples since they generally slow you down. I'd go for pain lands since Oloro is able to mitigate the life loss and since your deck generally gives you enough life to spare for them.

Spells:

I'm not sure what your Doomsday pile is. Sharing it in your deck description would be nice.

You can replace Library of Leng with Thought Vessel.

I'm also unsure of Bitterblossom's purpose in the deck. You don't seem to run stax so I don't think you really need it. If it's there for pillowfort-ish reasons, I suggest using Propaganda or Ghostly Prison or both instead.

Megalomania, thanks for really good feedback. Most people I ask for feedback just leave some token "Sun Droplet?" comment or nothing at all.

I'll go over your recommendations one by one:

I have recently been thinking of cutting Coffers (doesn't really do that much), but I can't for the life of me think of anything to replace it (Mikokoro, Center of the Sea? Boseiju, Who Shelters All? Dark Depths, throw in my spare Thespian's Stage for the combo? Land Tax for my 5 basics? Try for 9/3/3 manabase?). Once I figure it out, I'll look into replacing it.

Also, I really have an undying and completely illogical hatred of Forbid (one of my first times ever playing Magic, I got softlocked by it and had no clue what was going on), so while it is potentially better than some counterspells in here, I refuse to run it. Excellent suggestion, wrong person.

Temples are really more of a meta pick. Despite what the deck looks like, my meta is...remarkably uncompetitive. You're looking at arguably the strongest deck in the playgroup, and no one else is looking to win anywhere close to fast, outside of a Prossh deck that needs a god hand to pull of a turn 4 win. While I probably could get away with painlands, generally the scry from the temples helps A LOT. On the fence a little here.

I really should have been more specific about my Doomsday pile, it's hidden somewhere in the wall of text known as my description. Also, I really should revamp that. Huh. Anyways, it's really nothing too special: Laboratory Maniac, Brainstorm and any number of cheap counters, like Force of Will, Pact of Negation, Swan Song, Misdirection etc.

I have a spare Vessel lying around somewhere, it's just a question of whether I prefer ramp or not having to discard from Solitary Confinement. Ramp is probably better. Probably switch soon.

As for Bitterblossom, it's in here because this deck gets a lot of hate. Having a free Will-o'-the-Wisp each turn that can also be used to tick down planeswalkers if I'm not attacked is pretty darn good, IMO. If you can think of a better card in here, I'm all ears. It'll just be sad to get rid of my foil 'blossom.

Thanks for your help!