I'm sort of a newbie. I played AO back in Beta 4 and a little when it came out, but I quit due to the bugs and poor performance on my system.
Well, I got a new video card (GeForce 3 Ti200, very nice card, ) a few weeks ago and decided to give this game another chance.
Blah blah blah, enough filler, lets get to the complaints.
1.) Pet AI - The pets in this game are pitiful. My engineer has a pet a few levels above him (it's orange to me. I can't buff myself any higher unless I find some MP's, and I really don't care enough to). Sure, the pet is great when he WORKS. The pets can barely navigate the missions. I've heard there are "tricks" to get your pets to follow through every room, but that shouldn't be needed. Your pets should be able to navigate the rooms perfectly BY THEMSELVES. If that can't be done, I think the /pet follow command should make your pet follow your EXACT footsteps (just a few feet behind you). That way you could guide your pet yourself.
2.) Concealment - Does this even work? I remember that it was heavily bugged when the game first came out and Agents took major advantage of it. When my adventurer uses the Call to Greatness program (+200 to concealment), I still get attacked by every mob in a mission (even though I'm crouching and being very careful to avoid all the enemies). Granted, my my adventurer is only level 23, but 220 in concealment (the base of 20 + 200 from the program) should be enough to avoid most enemies.
I know both of those are fairly common complaints, but this next one I haven't heard of yet.
3.) Newspapers - I like the story in this game (all the conflicts between clan and omni and such, it makes it feel very realistic). However, I don't like how it's delivered. I feel that the game should be completely self-contained, and that you don't need to view an external website to get the story. So, what I propose, is to put a newspaper in the game. Yes, that's right, a newspaper!
It could be a little tab at the top, that when you press it, would bring up a sort of futuristic newspaper look, with all the big stories on the front, and maybe little comics or stories in other pages. I don't know how hard this would be to put in, but it would rock if it happened.
Okay, that's all for now. Thanks for reading this post, and I hope you consider these points.