lol thats a bummer for you, l personally don't like the many things in Aion, for instance, they tried to follow WoW in multi classing one class, WoW did it in talents, Tank/dps/healer was resolved here awkwardly to me, as far as l see it, you gain a class change when you hit a specciffic level, l'm kinda tired of this kind of change wich was actually pleasant in Ragnarok Online but every other game with this simply tired me out, and l think WoWs idea of simple talents was the most perfect that way.
Aion has too little classes to choose from, and personally l think thats quite unballanced, little veriety in this matter, WoW on the other hand had slightlty a lot classes (10 as it is now) and ballancing them out was very hard and still is, but at least you had enough of frontline meatbags (melee) enough heaers (shamans/priests/paladins/druids) and enough ranged annoyance in heavy boss fights, like mages, hunters, locks also so called hybrid classes like paladins shamans druids and priests as healers were very welcome however when they were tank/dps specced it was sometimes annoying unless there wasn't a lot of them in the group, especially paladins, since on my server, every instance seemed to love paladins anyways, so it was a paladin paradise for looting.
as a shaman l loved being in the center of attention when l was DPSing and some idiot tank lost aggro and a healer died, l was a backup healer thanks to being elemental with enough spellpower to actually support the raid group long enough for a druid to revive the fallen healer (or a paladin to sacrifice himself on me so l could ress teh healer but then healing wasn't enough)
that aspect was great if you pugged in raids, especially surprise puling by me ;]