Aion's downfall includes; NCSoft's irresponsibility (delaying on releasing patch notes, incomplete patch notes, delaying on release of patch notes just to name a few), unbalanced races (one race is completely favoured over the other, many argued, but all failed), ridiculous drop rate (running countless instances without seeing a single gold or decent drop), lack of endgame content (a given, but apparently being changed in future patches still to come), mages and rangers ruling the game (this is not going to change because they only get stronger in the upcoming patches...and that's a fact), and melee is broken (still hasn't been addressed).
That's just to name some of the major ones.
Am I still playing myself? Well I don't really play anymore. I stand around talking and doing a few instances here and there nowadays with close friends.
Am I going to quit? Not yet at least, still seeing how far this game can go, or how much worse it can grow, especially for some specific classes.