I still can't believe that anyone would think AonDor was too powerful... Thats like saying a bow and arrow are too powerful, because you've never seen them before, and don't understand their limitations. The first time someone got shot at by an arrow, they were probably screaming for fear of their lives... Flying sharp objects? No thanks! Not until they saw how the bow worked, how long it took to shoot/reload/aim, the limited number of space to carry arrows (and therefore limited number of arrows), did the person getting shot at realize that it wasn't that big of a deal.
AonDor is quite similar. People fear what they do not understand, if I saw fireballs flying at me, I'd scream and run like a maniac. If I was then given the chance to see how it was created, the time it took to draw the Aon, the time it took to learn how to draw the Aon perfectly (including the multitudes of modifiers), I wouldn't be as shocked.
Like others have said, AonDor is limited, but it in ways that MANY other magic systems are not limited. The way the land is shaped is a huge limiting factor, it took them a decade to figure out why their magic suddenly stopped working, and this is from the best AonDor users ever.
Another analogy I feel fitting: Many video games (games like Starcraft, or Heroes of Newerth) have a HUGE time stamp on them. They take months, if not years, to master every aspect, and every possible thing you might face. In fact, many things in real life are like this. AonDor may have limitless potential, but people do not have limitless memory, or limitless abilities. Saying "Anything is possible with AonDor" is correct, but what are the chances that anyone, or any 100 people could account for every possible thing you can make with Aons. Sure its limitless, if you ignore the distance from Elantris, and the shape of the land arguments.
tl;dr - AonDor has limitless potential, but who can use every single thing that AonDor is capable of?
