Target markers should appear in the enemy list to the left or right of the enemy names. It would help tanks and DPS a great deal.

The party needs to be able to quickly discern which target is which, target it, and resume fighting -- without having to look at the target bar, or cycle through the visible mobs. If every mob is indistinguishable from the next in the list, then the list itself becomes extra noise on the HUD, or another obstacle to contend with. It almost defeats the purpose of having the list in the first place.