memesis
One Thousand Club
For game-balance purposes, you might argue that. Â You could also say that, given the thousands of years of magical research, the schools of sorcery came up with better versions of the spells Brigid (or whoever) originally brought back that dealt with demon summoning, and that those advanced spells were kept under lock and key - explaining why the 'lesser' spells are all that people know today. Â I have no problem with this latter approach, because the game balance is then 100% in my hands - if I don't want my PCs having this, they don't have it.If you did this it should be in some way inferior.
There are other complications that can arise. Â You can say that the Essence channeled into the spell is gradual and allows for Essence regeneration to take place, but that means more contested Willpower rolls - giving the demon a better chance to escape. Â You can say that Essence given to you by someone whose motives for the summoning don't align with yours will corrupt the ritual. Â You could say that multiple casters can cooperate on the spell, but that their hearts and minds must be absolutely unified on the demon's task or it goes free automatically.
You can certainly increase the risk of something disrupting the spell - resisting distraction becomes more difficult, perhaps.
I frankly don't care. Â I see Exalted sorcery as something akin to industrial technology in terms of how it is developed and how it works. Â Spells that are just flat-out improved versions of other, better-known spells should be possible, and there are all sorts of reasons why they are not also widespread (everyone knows how to make fire; some people know how to make gunpowder; very few people know how to build a nuclear bomb - you figure it out). Â If that's the sort of game the ST wants, he should have it.