If you really want to dabble in your classic blue magic FF trope, I'm afraid we don't really have anything in lore right now as far as I know. But as suggested above you can wait for the next fanfest and see if the next revealed job for 4.0 will be blue mage. That way if it's the case, then you might have a safer framework to work with, even if you will still lack most of the specific history, classquests and lore specifically tied to the class in Eorzea. For that, you will unfortunately have to wait for 4.0, if blue mage is confirmed that is.
However as you say, summoners tend to learn their spells and magicks when directly or indirectly confronting primals, or primal essences. That's not exactly blue magic as they don't learn it by being hit though, and their learning is limited to primals only, not your average everyday (or less everyday) creature of Eorzea.
A summoner could totally mimic Ifrit hellfire, since we know for certain that at least the WoL can mimic Bahamut's Deathflare and Painflare when they get frustrated that the Elder Primal is too much to chew when it comes to directly summon him. We also know that Tristan, the antagonist of the SMN quests, replicates Ifrit various abilities. Since we know that lesser primals like Ifrit, Garuda and Titan can be summoned as gimped versions of themselves (Egis), I don't think it's too much of a stretch to conclude that their abilities should not be a huge deal to learn for summoners. It becomes way harder with bigger primals that you can't directly summon, being too powerful for that and out of reach (for now).
Then you have the unconventional Allagan road I think. We know for example that Ultilma Weapon was able to directly syphon primals and store their energies, spells and abilities in its aetherochemical tanks and advanced computers. And cast them at will, as shown in the assault on the Praetorium when facing Gaius in control of the Ultima. Well, that's super advanced prototype allagan tech though, so... It might not be the most accessible thing ever, but that's a possible mechanic lore wise.
However as you say, summoners tend to learn their spells and magicks when directly or indirectly confronting primals, or primal essences. That's not exactly blue magic as they don't learn it by being hit though, and their learning is limited to primals only, not your average everyday (or less everyday) creature of Eorzea.
A summoner could totally mimic Ifrit hellfire, since we know for certain that at least the WoL can mimic Bahamut's Deathflare and Painflare when they get frustrated that the Elder Primal is too much to chew when it comes to directly summon him. We also know that Tristan, the antagonist of the SMN quests, replicates Ifrit various abilities. Since we know that lesser primals like Ifrit, Garuda and Titan can be summoned as gimped versions of themselves (Egis), I don't think it's too much of a stretch to conclude that their abilities should not be a huge deal to learn for summoners. It becomes way harder with bigger primals that you can't directly summon, being too powerful for that and out of reach (for now).
Then you have the unconventional Allagan road I think. We know for example that Ultilma Weapon was able to directly syphon primals and store their energies, spells and abilities in its aetherochemical tanks and advanced computers. And cast them at will, as shown in the assault on the Praetorium when facing Gaius in control of the Ultima. Well, that's super advanced prototype allagan tech though, so... It might not be the most accessible thing ever, but that's a possible mechanic lore wise.
Balmung:Â Suen Shyu
