Originally Posted by
Lusavari
Your theory is also consistent with what the Sylphs had to say. They always said that the scaled-ones and feathered-ones were not violent until after they called the Primals. Another thing, though, is that the Primal summons require large amounts of crystals to summon them. The official page says "In times immemorial, there lived mages who had not only the power to summon the primals, but also the means to transmute the primals' essences, thus binding them to their will." So transmute means to change the nature of something, and then they bind it to their will. So my line of thought is Summoners must acquire a fraction of the Primal's power, which they can then command.
Let's also think about weapon choices here... Traditionally in summoning mythologies, you see summoning circles, or patches on the ground made for summoning creatures. We start to see them appearing in X, but they also show up a lot after X. Let's assume that in XIV, the Summoning Circles don't magically appear as part of the spells (The Beast Tribes seem to like summoning in specific places and have what's needed for ceremonies out ahead of time). The books provide easily mobile summoning circles, and probably lesser consumption of summoning resources (Magic, crystals) which would explain a smaller size, and incomplete summon. I like to think though, what's being summoned is just their essence, which is then bound to a catalyst like a crystal, giving them shape.