Enemy Hp

[Nexrex]

Exactly, you just said it yourself : the UI should tell you what's happening. It should not tell you things you have no other way to know. When you buff yourself/others, or you/your enemy receives a debuff, you know it. The UI is merely showing what you already know for convenience. Someone's HP in the other hand is only known to him. If you want to call a priority target you need to go through what you would actually go through if you were a character inside that fantasy world :

1) You would have to determine the profession of the enemy and deduce the armor weight.
2) You would have to exchange some hits with your enemy to determine both what are some of his main abilities, some of the boons/conditions he applies and preferably what are his weapon combos.
2*) You would also have to conceal your own main abilities for a moment and try to throw you enemy off-track
3) You would have to compare the new information you got by messing around with the enemy with other popular builds for that profession and deduce what build he is most likely using (the more knowledgeable you are about that profession, the better)
4) You would have to react accordingly and hope that your predictions were right

At 3) you will have an estimation of your opponent's health, so most skilled player WILL have an idea on who's squishy and who needs to go down ASAP. If you're not able to go as far as 3) then you won't and you will have to take a guess. That's what's commonly known as a high skill cap. Now compare this to : "Gladius shows Balance Druid. Nuke him !". Playing the UI vs Actually fighting.

^^Thousand times this and /thread
Perfectly put. Especially that last reference. It's exactly that aspect that makes me, a decidedly pve player look forward to pvp in guild Wars 2 a lot ^_^

[Newbryn]

Shit I remember when a lifebar was more than enough info. Also personal opinion but I kinda don't like life bars or hp showing, the fight feels more intense and desperate not knowing when your enemy is going to die, one of the main reason I only play vindictus missions on hard.