This is the heart of the matter. The supposed Trinity was Damage, Control, and Support. Given the high-mobility facet of the game, the latter two roles would demand a high level of precise timing and teamwork. To that extent, GW2 might have been an fast-paced action game, complete with specific and crucial counters to incoming attacks.
Instead, ANet rushed GW2 out the door, slapped a horrible buff, Unshakable, onto PvE boss mobs, generalized the professions to the level of brown mush ("if everyone's special, no one's special"), and shipped it that way.
Ever since, the devs have desperately tried to argue "working as intended," despite over a year's worth of play time showing otherwise. And rather than fix these fundamental problems, they cling to PvP like rats to a sinking ship hoping eSports will keep them afloat.
Don't get me wrong--I like GW2. I just wish it'd become what it was touted to be.