This effect seems mythic and like it should cost more styled like Rise of the Dark Realms.

I was remiss in not mentioning that otherwise the whole concept is a really cool and unique idea, if somewhat problematic in practice.

WHat elements are probleatic? I know it's going to stink when you end up casting all the blue player's counter spells. I would like to know, so that I can modify the card to address those issues.

The possibilities of things going badly for you or having unintuitive interactions suggests a more forgiving template. "Exile all cards from all graveyards. Choose half the nonland cards exiled this way, rounded down. You may cast the chosen cards this turn without paying their mana costs."

I don't think is mono-red, though. A, it's graveyard hate; B, red can only recur instants, sorceries, and Phoenices.

I think the incidental graveyard hate can be forgiven on a 9-cost sorcery. But I agree that the ability to return permanents is a straight on pie-smashing contest, even if the choices are done at random. "Destroy target enchantment at random" isn't a red ability, so I don't see why half a Twilight's Call would be random either.

Also, when everything happens at once (as opposed to using something closer to dude's wording) targeting becomes a problem. If a creature is returned, and Reckless Charge is cast 'all at once', you can't target the returned creature with Reckless charge. Which is problematic, since many players would assume you can (otherwise, why would the spell be okay with letting it happen this way.) Note that in the case of Warp World, and a few other cards that operate like it, that the non-enchantment permanents enter the battleifield first, then the enchantments, so the auras have something they can target (though the 'enchant enchantments' all go to the bin. Strange, but true.)

WOuld permanents being returned only until end of turn be within red's color pie? Red did have unearth as a precedent. If red doesn't have any artifact recursion, I could at least imagine it being within red's slice. Enchantments and planeswalkers would become the sole outliers. If I keep this so that all cards are cast at once, non-aura enchantments have a lower probability of being useful, and auras will only be useful for permanents you already have out (or even detrimental if you don't have any).

Unearth is an interesting precedent. Two of the four mono-red cards with Unearth are Hell's Thunder and Hellspark Elemental, which sacrifice themselves at end of turn whether or not they've been unearthed. That feels more like 'ground-based direct damage'. But Vithian Stinger and Scourge Devil are just straight up creatures. So yeah, Wizards was willing to reach for this, at least back in Alara. But keep in mind, the mechanic was also in blue, which is probably the last color that mechanic should have been in. They really played fast and loose with the color pie and that mechanic.

For Red, though, I figure Wizards considered unearth to be a variation on the Sneak Attack mechanic, which pops up from time to time. It's somewhat unusual, but if you template all your permanents to gain haste and sacrifice at end of turn, I'd say you're okay.

Is this okay even for enchantments, presuming you sac/exile at end of turn? I could see someone arguing that off the concept that 'no color has attempted to sneak attack non-creature permanents, so Red is just as likely to be able to do it as any other color.' Maybe that's a valid argument, or maybe it's tripe. Unsure.

I will say this much, though. Even if all permanents got cast 'at the same time', they'd still all need to go on the stack. So I presume they'd end up being ordered in the method that is best for the caster. You can always make the Pyroclasm go off before your creatures hit the table, for example.

I forgot about artifacts. Red does get a little Goblin Welder-style effects