due to narrative, lore, and magic system updates, I would like to congratulate elite employees Carver Hawke and Taash on their promotions to the illustrious Technically Mages But Lack the Talent to Actually Do Magic Department, where they join department head Minaeve in representing the spectrum of mage power in Thedas.
the lore tidbit that some mages are too weak to even light a candle has always been fascinating to me, but even including Minaeve, it wasn't really utilized.
With Minaeve, she already has the perfect back story to demonstrate how a lack of talent may affect someone. Like all Dalish clans, hers prized their mages - but unlike most, her clan took it to an extreme (mage supremacy, now not just in Tevinter). She showed promise by presenting as a mage early, but disappointed everyone with her weakness. Her lack of talent meant she was of no use to their clan, and sending her to another would embarrass the clan's reputation - so that's why she was cast out to "find her own way" (as in, die of exposure). An unfortunate and abnormal situation that she carries with her as an adult, informing her opinions on the goings-on of the mage-Templar war.
With Carver, the change is primarily because Hawke can't be a mage in MFDA2. I don't buy that a blatant apostate who kills a dozen+ people every time they set foot outside would be able to become the most important person in KIRKWALL of all places, and I think "Hawke spends half the game fighting tooth and nail to protect their mage sibling only to fail them spectacularly" is such a compelling story that it should be thee story. So Carver and Bethany are both mages, and which one of them is killed in the prologue is random - senseless, violent, unpredictable. Carver's resentment of his siblings is, as ever, rooted in feeling not good enough in comparison. He and Bethany have very different experiences and perspectives on being mages.
With Taash, being an adaari means they have the ability to tap into the power of their dragon-blooded heritage... which is magical power that comes from blood... so they are technically a blood mage - just one that's only capable of performing blood magic on themselves. It's a sort of "path of least resistance" situation; a qunari mage-child who lacks the talent to reach the Fade may still be able to reach within for power. They could do other things with that power, but adaari are so culturally important that fire-breathing is how it typically presents (mage children of all races love setting shit on fire); and by training it exclusively, they lose flexibility to learn other skills. A particularly powerful adaari may be able to perform blood-magic-like feats on others or access minor Fade magic, but generally they are only able to utilize the magical power of their own blood. In qunari culture (and by extension, Rivaini culture), adaari are adaari, not mages - so Taash doesn't think of themselves that way, nor does Shathann.