Also you could inscribe healing aons on the inside of your armor to heal you when you take a hit.
Or on rubber tiped arrows, to shoot near injured allies.
Possibly consider having a sack filled with aons inscribed on paper, so you can activate them without taking the time to write them mid battle
As I see it there would be two ways an elantrian could wourld-hop. They could use the travel Aon, which would be a one way trip, because they would be to far from elantris to use it again. Or they could some how use the spirit aon to enter the cognitive realm.