Personally I didn't like Aion much, it's definitely pretty but to me that's about all it had going for it.
It's probably a good game, with high production values, but I didn't really enjoy it.
The problem I had was with the gameplay itself, I found it pretty meh. Everything felt a little too slow paced.
Weapons took too long to swing, cast times were too long, cool downs were too long, instance mobs took too long to die, gathering took forever, too much walking etc..
Although I think it was the part where I kept getting ganked by asmos every time I took any attempt to seriously level, which really put me off in the end.
I played for about 1 week, got to Lv24 or so and quit.
Quite likely I didn't give it that fair a go, but really didn't feel like playing any further.
I definitely enjoyed WoW more than I did with Aion, but honestly the games themselves are too different for a fair comparison.
And Nick NO, WoW did NOT have massive drop rates.
Imagine 3-15% drop rates for raid content, 1 attempt per week 2-6 hours per raid;
split that between 25 players, it's not entirely rare to actively raid for a year and not get the piece you wanted.
Not to mention, that is assuming you are in a guild that is even capable of handling the content.
So yeah I wouldn't exactly say WoW players were spoilt with high drop rates!
And no I stopped playing WoW aswell haha, so I'm not being bias ;]