I think what we're all missing is the roles from eq. The support role has died and pulling? That was an art.The trinity has really dumbed down mmos.
The trinity, in its current form, leave no expansion on roles other thank EHP, DPS, and HPS.Sure you can get even more specific like Avoidance tank vs Mitigation tank, Range vs Melee and Single target vs AE, but these roles still have one common goal.
IMO the trinity is still the same, what has changed are some very specific class abilities. I mean FFS, EQ1 was core trinity/diku design, just with some added (and possibly in the long term, unintended) mechanics.
Support (Controller) - These people control fights. They knock down enemies, blind them, confuse them, all around beat their senses.
There are plenty of classes across a number of MMOs that have scads of abilities like this. Many are, arguably, of short duration, but they are there. WOW Rogues might be a good example, it might be arguable, and I'm sure that others can come up with many other classes as well.
Puller - These people also control fights, mainly the beginning are important in how they setup the pull. They could lay traps, devise routes, and are really good kiters.
You just described good Hunters in WOW (emphasis on "good"). They may have changed since I last played WOW, but when I did play regularly I knew a couple hunters who could have me pull, tag one and ice trap it, then tag another and kite it if necessary. Obviously the clock was always ticking and we needed DPS to burn the rest before traps wore off, but that's just one example off the top of my head.
pulling? That was an art.
Sure it was, but it was capable of breaking content. And a good FD puller could split off single mobs that were never meant to be splittable. But Devs aren't going to want one class to be able to trivialize content while others cannot, and that was a huge failing on the part of EQ1. Hence the changes to FD mechanics (I'm looking at you EQ2), hardcoded encounter mobs and mob leashing. And honestly, FD pulling and things like mass trains and AE kiting an entire zone are often the bulk of what a lot of the EQ1 vets actually complain about but it isn't likely that we'll ever see any of that again in those forms. No Dev is going to want to allow people to pull entire zones or dungeons, they aren't going to want training, nor will they want certain classes to be able to single pull every zone in the game.
FD pulling at least I think was nerfed too much, since you could probably link mobs together and make them unsplittable without having to change FD mechanics themselves, but whatever.
Bosses are no longer 'fixated' on tanks through threat alone. It is the job of the support and a tank to keep the boss focused on him. Tanks would have more abilities to jump in front of bosses and save team mates.
Tons of MMOs now have abilities that the non-Tank classes have to use. Talk to anyone who has had to boot a DPS class from their group because they wouldn't use deagros or anything similar, or who didn't know that their class had a hate transfer. And honestly, as someone who has mostly played tanks in MMOs, the last thing I would want as a tank is other people in my group having to bear part of the burden of managing mob agro or being somewhat responsible for who a mob attacks. Because frankly that leads to having mouthbreathers dick things up because it is no longer solely controllable by the tank, but the tanks usually get blamed anyways. Let the support assholes support and let tanks do the fucking tanking. And don't even get me started on things like hate transfers and support class deagros, because any variation between classes can lead to people min/maxing class makeups and that leaves the other classes begging for groups because they aren't quite as good due to class design.
Few things infuriate me more than having pulls go to shit because Devs decided to give non-tank classes MORE agro/deagro abilities, which means that agro/tanking will be balanced around everyone doing their job so that when little timmy buttonsmasher is trying to go MAX BURN DPS on every pull I have to burn taunts because they can't be bothered to do their part on agro management.
Give support more of a role with agro? Sorry, but FUCK NO. I say give tanks better tools to manage agro with if you're going to go with an agro based system, because by and large most DPS players are fucking idiots.