I'm going to try and say this as absolutely concisely as possible:

The ability to intuit one's enmity level without a hate meter (as a mage/damage dealer) is a skill that is based on one's experience as a player. It is one of the few things in a MMORPG where the person behind the keyboard matters, and not just the character in-game.

The lack of information about the monster's enmity list (except for knowing who is at the very top) is one of the biggest things that 1. makes battle exciting, and 2. makes a difference when the players are actually skilled at their jobs.

As a tank (this depends on whether they choose to implement volatile and cumulative enmity like in ffxi), it is your skill as a player that let's you intuit that you've been beaten up so much that you need to save up a big VE spike ability for when the monster turns its eyes towards the healer. So yes, to all the people saying that tanks are just going to "voke cure cure cure cure voke cure cure cure cure" ad infinitum, there IS more to tanking than that.

As a damage dealer, a skilled player will be able to "ride the hate line", dealing as much damage as humanly possible without taking hate. With the enmity meter, this is no longer a skill that requires any thought. This is simply "press buttons until meter reaches point A". We should not be endorsing changes that bring the game closer to ProgressQuest.