I'm a huge fan of customization. I can spend hours fixing my UI. After all, if I'm to look at something for hundreds of hours, might as well make it JUST the way I want it. I must have a hundred addons on WoW, and while some addons in WoW history were really too much and were nerfed by the devs(like the old decursive and some healbots addon that would choose both your target to heal and the spell rank to cast for maximum efficiency), most addons only enhance play experience.
You are never forced to, say, look up your questing addon, but if you don't have it, you can be sure you are going to ALT-TAB out of Aion and go to the new Aion quests database website when you are tired of running around aimlessly.
I think no addon should take decisions for you. But I couldn't live without the others.
UI customisation is fun:
http://i96.photobucket.com/albums/l1...al/panther.jpg