Some of the problems I see while raiding, in situations where multiple mobs are involved, whether its trash or adds, is more of a coordination issue. When two or more tanks are fighting for the same mobs, others run free to do their damage. In this case, in my eyes AE aggro is the tool that works around this form of miscommunication. Often times, mobs are all named the same, so you can't just say i am taking xxxx mob, or you get yyyyy mob. Is there a better way, maybe.
If tanks had a way to mark mobs instead of relying on hott, and chancing proximity aggro, slight ae aggro, or heal aggro on multiple mobs, in my eyes it can only improve tanking ability, raid survivability, and class squabbles. The way I see it is some form of aa, instacast that puts some form of graphic with your name, on a particular mob you are trying to aggro. All marks would have to be equal, and they would not overwrite each other, so that once something is marked, you cycle to the next mob to mark it, if someone else had the mark on the first add. No aggro should be involved in this aa, it should just be a coordination tool, for times where seconds count. If paladins get this new form of ae aggro, limited to 4 mobs, this mark extension can be included to that particular spell, aa, disc whatever. There is already the ability to mark mobs through group leader aa's, so functionally the tools are there.