For me it depends entirely on the pull (the size and what particular mobs are in the pull), the group and how the tank is holding hate, and what job I'm on at the time.

If I'm on SAM, I'm usually trying to keep up my speed and damage buffs while mixing in AOE, but those buffs are from single target skills, so no, I'm not AOEing 100% of the time on SAM (it's only 64; maybe that changes later).

On BRD I no longer have Flaming Arrow or Wide Volley, I can't spam Rain of Death, which leaves me with Quick Nock. With Tactician and Invigorate I can spam it for quite some time, but not forever, and there are times when there's a single target that needs to be focused down first. If the tank pulls something like that plus a huge amount of trash, I will focus down the one big mob that's likely to cause a problem first before I switch to Quick Nock. Plus I'm always trying to keep up my bites for the procs on songs, so I need to make sure I don't miss an Iron Jaws before the bites wear, or reapply to another mob.

On RDM I often use AOEs, particularly Scatter, but I also pay attention to my Ver procs so that I'm not losing the mana points for Enchanted attacks, one of which is a really nice AOE. Contre Sixte is great, but I can't spam it, and I've pulled hate using it too early, so I have to wait till the tank has established hate on the entire group.

It's situational. What job am I on? What's the pull? How is the tank holding hate? Is there a particular mob that needs to be focused? How's my TP? Are Invigorate or Tactician ready? I don't just blanket go in and spam AOE. I treat every pull differently and react to what the situation is. Just last night I was running Kugane in expert and the tank was struggling to keep hate, so I had to make adjustments to what I normally do. I look at the situation presented and ask myself, "What's the best approach for this fight?"

So should a player be using AOEs? Yes, absolutely. But, IMO, they also need to be mixing in other single target skills, depending on the job and the situation. But I would never kick someone for not using them. I would politely recommend it would increase their damage output. But if they refused, no, I wouldn't kick them. It's not something that would even remotely upset me. I'd shrug, adjust, and move on.