To be fair, the players did that. There's nothing wrong with identity in the trinity. There's something wrong when every design incorporates going as fast as possible as efficiently as possible. That's why tanks and healers are dps classes with extra steps. But the trinity is fine as it is. Like I said, every game that breaks from it eventually comes crawling back to it. Getting rid of it won't make them feel better. It always makes them feel worse. Being a "tank" in GW2 is the damn most unrewarding experience in life.
Personally, I think harder dungeons and more involved rotations removing the agro system of lack there of we have now is a move in a better direction. Make a mob of enemies threatening so the healer can barely dps instead of only dpsing. Giving players options to CC enemies and making the experience more of an experience and less of an endurance test to stay awake.