What if New Phyrexia was sent back in time through Sarkhan time nonsense and he became the "dragon" creator of Phyrexia and New Phyrexia was Old Phyrexia all along?

Easy there, young man. Don't make me phone your parents.

Who hurt you?

I still like my farcical head-cannon that planeswalker sparks are just Eldrazi titan dander that drifts through the multiverse, occasionally bonding with souls as they are forged for their mortal realms.

I mean, since we are throwing around random ideas...

- I'll riot if they don't reveal the name of Innistrad's fourth angel sister to be Lysene and finally tie up that throwaway line from the Zendikar novel. (I've been vocal about this for years, and Azure even suggested the idea to Doug Beyer at a panel, so, fingers crossed).

- I'd fix Aminatou by revealing that she doesn't have quite the power she thinks she does, but that she was actually born with an Entity inside her that has been manipulating her (you know, those remnants of worldsouls that show up in Children of the Nameless). I'd establish that being born that way automatically gives you a spark and that Tacenda also became a planeswalker in CotN, which means she could now meet Aminatou and help her figure out what's going on. All of that could then connect to Davriel somehow and touch on his mysterious backstory. Because Davriel is awesome.

- Zur the Enchanter found Jodah's Fountain of Youth shortly after the events of Coldsnap by reverse-engeneering that magic detector that Jodah used in the Alliances novel. He fled north with the remaining members of the Rimewind Order and is now the Immortal King of the Northland, pulling all sorts of strings behind the scenes for his great conspiracy. Garza Zol, Plague Queen and her Krovikan Vampires are probably still kicking there, too, all waiting for another Snow-themed set called Dominaria: Northwind.

- Greensleeves was still alive during the Phyrexian Invasion and gave her life to shield the rebuilt village of White Ridge and the surrounding forests from Yawgmoth's deathcloud. Her ghost is said to be seen in the Whispering Woods occasionally.

- Towser ended up in the city of Coraleon to join the Festival of Sorrow after losing his magic powers in Final Sacrifice. He stayed there and became the master of the festival eventually (after that crepy green lady we see in 'Festival of Sorrow').

There have to be 3 eldrazi titans. Whenever one dies another being is elevated to the position. Some of the more notable eldritch horrors on Innistrad were the multiverse's attempts to replace a titan. Eventually one of those attempts is going to "stick".
The Gitrog Monster had a pretty creepy uncharted realms story...

That's Emrakul's role. Ulamog eats all the mana. Kozilek collapses the entire plane, space and time. Emrakul assimilates and uplifts organic beings into Eldrazi mass.

The fourth Eldrazi is Manatarqua, who was resurrected by Niss with her leyline coding.

You know, there's a serious question that just hit me, which was probably a byproduct of my idea for Aminatou: Could Liliana's Raven Man be another one of those Entities?

It would probably be weaker than Davriel's, but why should all Entities be exactly the same? It's glaringly obvious that they never had a plan for the Raven Man, or at least none they followed through on, so I guess it's possible they'd just take this new concept and make it fit somehow. Personally, I really don't care about the sorry remnants of Liliana's character and story anymore, to the point where I'd be happy to see her killed off. But from a purely theoretical perspective, I wonder if that could be the route they are going to take with that Raven Man mystery. Heck, at this point the Raven Man is probably the only thing worth salvaging from the mess that is Liliana. Whatever that guy is, his story might continue without Liliana somehow. There was a time when I really wanted him to be Lim-Dûl, but the state of the "storyline" being what it is, that would just be another old character they'd drag down and ruin, so I really hope it's not him.

Its acthelly Leshrac's long lost cousin's brother's son's lover.

You mean Volrath?

Here's a what if I'm legitimately interested in hearing thoughts about:
What if Urza had been lost in the desert and Mishra had shown up in Yotia?

I had a dream last night where unicorns could "move through the country as a bullet and through the city as a plague". That is, they could literally turn into a bullet as a means of travel. And they literally transmuted themselves into an infection to... travel or I guess hide. Also it's how they reproduce; if the disease infects enough people, instead of transforming back into 1 unicorn it becomes 2. The process is fatal to the infected humans and the disease spreads through social, not physical connections.
That particular dream sequence had a BPRD: Hell on Earth meets Mad Max apocalypse vibe. And yes, I feel this is one of the best ideas ever.

Abzan Unicorn tribal then.

pitch it to Rush's latest set building project and see if he approves