Summary: offensive spells that are not yet in the game (and which job could get them)

[Archwizard]

Apocalypse
Burst
Dark
Meteor (Comet)
Quake
Tornado
Ultima
Water (Aqua/Flood)

First: Meteor is already the BLM LB3. (In PvP, their Limit Break is also named "Cometeor".)

Second: Ultima exists within the canon of XIV, and is demonstrated during The Praetorium. As Ultima has been shuffled between White and Black Magic many times within the series, I expect XIV is going with the interpretation that it belongs to neither school, particularly since it was a capability of the Ultima Weapon, an Allagan machine that predates the War of the Magi and needed to consume three Primals -- gods given form by pure aether -- to cast it.
In short, nobody gets it, good day sir.

Third: Earth, Wind and Water magic fall under the purview of Conjury, not Thaumaturgy or Arcanima. Should Quake, Tornado, and Flood ever be added, they would either be given to a White Mage or (Yoshi-P willing) a Geomancer. Hopefully some form of offensive Water magic will be added to WHM and RDM.

Given it falls under the same line as Freeze and Flare throughout the series, Burst is most likely to be an advanced Lightning spell for BLM in the future, possibly even their level 80 spell. Who knows how BLM will change in ShB, but I can only hope we finally see the lightning spells as more than self-contained DoTs through Burst, perhaps even tied back into Enochian.
(That or... just rename Thundercloud. It'd basically be the same thing.)

With all the obvious ones out of the way, that leaves... Apocalypse and Dark. Admittedly I have been curious if Foul is intended to be BLM's attempt to utilize Dark-type magic, given the lack of precedent or lore behind it. There's no "Dark-elemental" in XIV (and to be fair, elemental damage is mostly for the player's benefit than the enemy's detriment), so there's not really a particular place for them.
Assuming Apocalypse isn't marked off as an equal to Ultima (and the fact that it's been used as a Grimoire name doesn't remove it from being a spell), I could see it being the "ultimate Black Magic" to be learned when BLM reaches level 100 or somesuch, or perhaps some type of high damage DRK skill to put its output closer to WAR's now that Yoshi-P is enforcing the MT/OT balance with GUN.
Or, maybe we'll see both of these in the hands of a future DoM, like a Necromancer or Void-based class -- Dark as a Lv1 spell, Apocalypse as a limit break.