High Value Target (HVT): A target the enemy commander requires for the successful completion of the mission.The U.S. Army (and other Armed Forces) use these terms to help plan battles. Team PvPers understand the concepts even if they don't use the terms. A good Artificial Intelligence will understand it too. Traditional MMO aggro tables try to mimic what goes on in the enemy's head. But as is easily seen by the fact the Tanks tend to be useless in PvP, aggro tables are a poor substitute for an intelligent opponent.
High Payoff Target (HPT): A target whose loss to the enemy will significantly contribute to the success of the friendly course of action.
~~ADRP 1-02, Operational Terms and Military Symbols
PyroChem Engineer, complete with increased endurance and aggro manipulation. I could pull aggro on any creature driven mostly by that mechanic. Most of GW2's professions are very flexible, too. I was also able heal on the fly simply by changing out my kit. But ArenaNet's goal was to not have those roles be absolutely necessary for a dungeon; therefore making it easier to form groups and tackle the content.
It's easier for me to come up with reasons to get rid of traditional Tanks than reasons to get rid of designated healers. But again, a la GW2, giving each character the ability to heal themselves takes the burden of healing off a single healer or small group. GW2 does allow for designated group healers, but their healing is weaker, compensated by the fact that everyone could and should be healing themselves.
How will SOE solve the question of roles in EQNext? I don't know—I don't think we have all the information. Honestly, SOE may not have the answers fleshed out either. Maybe they'll take feedback and incorporate a version of UT into the game. However, I'd like to see a different approach than aggro manipulation to drive group content. The use of voxels may be the key to that alternate approach. If a tank can physically block the enemy from the DPSers and Healer, that would be something.
What do you think? Is SOE going down the wrong path in trying to eliminate the Unholy Trinity? Do they have something else up their sleeve that might be even better?