Few Questions

[Anova]

The tab option changes the target to the next one from left to right. It doesn't matter if its a 1000 meters away or 1 meter. To help with that, I usually position my camera so only the current set of enemies is in view. A top-down view is used in the most extreme cases such as open-world FATEs with a lot of non-FATE adds. It's harder to do on some dungeon runs than others as well. In the worst case scenario, you select a target to the left witha mouse and just tab to it quickly. The developers have discussed that they want to change it, but I have no idea how yet.

I haven't used the enemy list yet, although I think it lists the targets you have hit already. Tanks will usually use a skill called 'flash' or 'overpower' when tanking. This is an aoe aggro-generating attack that prevents healers and dps from pulling aggro on them. Because they always open up with this and intentionally target every enemy, you might get the idea the enemy list is different for them. It really isn't.

That kind of activity depends on the players, server, and time. It is usually a specific subset of players who do open world chats. You just have to find out what times they are online and where they are. It's most common for players at endgame who are just waiting for dungeon queues or are otherwise bored. You'll see more of it as more players reach end-game. I'm not certain about the Lich server, but ul'dah is usually a hub for social players (it is very central to the entire map). Limsa and Gridania are much quieter.

[Mordrim]

Thanks for the answers guys, especially Anova i understand better now and as i play zoomed out fully that's probably why i get so many mobs through the cycling.. I'll try to focus the camera more when needed. cheers!