I’ll have to agree with you; the way spells are cast, as per the AD&D 2e PHB, states that they have to move a certain way / say the right words / have the right spell-components in order to work and mages have to spend years learning the right way to cast spells; magic-on Athas seems to using a more powerful-source.
Dark Sun’s a little strange with it’s magic; using the power to turn a Type O star (Blue into a type G and then into a Type MIII, (red-giant), it enough energy to vaporize Athas, like a million times over.
Magic varies from world to world; I actually know little about AD&D’s magic-system, as I just recently read up on the Magic-Users in the AD&D 2e PHB (I’ve had the book for like thirty-years and never really read up on that section). There are a lot of gaming-systems out there with their own take on magic such as Mage: the Ascension, where magic-users have their own innate magical-ability where they can bend reality to Second Sight, which may or may not have magic akin to religions-belief to Cyberpunk 2020, that had magic as belief with a skill, a very, very, very difficult skills to A Song of Ice and Fire, which has magic cannot take from nothing and game-wise, it takes a lot, and I mean a lot out of your character to cast a spell.
I agree almost completely wit this statement. Of course a normal mage would try to reach out to their power source and find nothing but the Grey blocking him. I do believe that a magic user from Athas would still be able to draw some power from nature as they are trained to do. This may or not work as intended due to the gods of nature and magic seeing this disgusting defilement of their power. I think any who continued to do this would learn to harness it better over time and attract many enemies. It’s something that could go any way the DM feels but this is my opinion.
Random thought… if an Athasian arcanist could connect to another source of power other than life energy, wouldn’t they still “rip” the power away from said source due to the nature of defiling?
Might have interesting story effects if said sources objected and considered Athasian arcanists a plague and a menace.