As a quick-hit for my initial thoughts on Aion, what's up with Aion himself? Not the most reliable god by any stretch... he totally screwed things up out there. It reminds me of when a government notices a pest problem, then introduces a species of animal or plant to combat the pest (look up Cane Toads). Next thing you know, the new species has become the pest and now we need a newer species to fight the new pests. Things get out of control fast. You'd expect, however, for somebody purporting to be a god to not be such a screw-up. With that, I'll comment on some of the concerns about Aion the game that are floating around out there.
"Quests are repetitive and there's too much grinding!" If those are the biggest gripes about the game then I'd say things are going well. Find something in the game that is worth more than just hitting the level cap. Join a guild, work on crafting, etc.
"There's no endgame! I've nothing to do now that I am at max level!" Ultimately the endgame of Aion is PvP, not raiding or questing or storyline of any kind. This should be obvious from the core game mechanics, pitting one faction against another in an eternal power struggle. Love it or leave it, I suppose.
"The flight is too limited!" The flight system is working great. People enjoy the flying and are having a good time with it, enough that they want more of it... that's great, easy update in the future content additions.
"Character customization is lame, everybody looks the same!" I am not sure why anybody would think this, it's simply not the case. Sure, when everybody is wearing the same armor their armor will look the same, but the potential for creating very diverse-looking characters in Aion is definitely there.
"The game is too buggy!" First of all, all games have bugs. With the amazing diversity of hardware out there running this game, I am sure many people have performance and stabilty issues. This is something that's going to have to be handled by the software development team stateside, and the jury is still out on whether or not they will adequately address the situations that are out there regarding some of the nastier bugs. Give them some time on this.
"There's too many kinah-farmers and people botting their characters!" This is one real problem which is endemic to NCSoft games. It will not go away. NCSoft has never truly cracked down on the farmers in any game they've done, and I don't expect them to change things up for Aion. If you cruise some of these money-selling websites it almost seems as if NCSoft has sponsored some of these groups... and that wouldn't shock me at all. Also, read about how many bots and farmers there are in Korean Aion over a year after release... it'll chill your bones.