I believe the issue is how many ways we use "healer" and "trinity."
The trinity works different in PVE and PVP. Simply because PVE is against dumb AI that stands around allowing taunts and heal spam and what not. In PVP, roles can change completely and moment to moment.
"Healer" doesn't really mean much. Every class in GW2 isn't a healer because it could self-heal/rez. Nor does a "Healer" in a game like DAoC, only heal all day.
I much prefer Support when describing the Role. Support can come in numerous versions from healing, CC, cures, buffing, debuffing, and other utility. All of which helps a team survive. Sometimes more offensive, sometimes more defensive. Just like a Tank. There are meaty 2-handers dishing out damage while taking it and Sword+Shield ones mainly soaking it up while doing CC. Similar Role played differently. MOBAs which have very few skills highlight this very well. Everyone can DPS, but not everyone can heal or CC or whatever.
If people want to stand 100 ft back and spam heals all day, that is useless and adds nothing to a PVP game focused on strategy. Why not just give everyone 500% more HP? Since the end result is the same, minus someone isn't standing there going Heal, Big Heal, Group Heal, HOT, Heal.
This is not strategy "Alright, when you get low on HP, I'll fill them back up." If this is an option, it becomes forced to have a "Healer" doing that at all times or be at a huge disadvantage. Hence the whole "Holy Trinity" and why it is so one-dimensional. It is either follow the pre-made blueprint of how to play or suck.
However, when "Healers" are given lots of tools to work with, they become extremely vital to game play. Which can and surely will include some forms of "heals" in CF, but there are so many other things to give them. When they are part of Offense/Defense with CC/Utility as well as DPS/Heals, it allows for a lot more options and player control.
GW2 not only lacks the Trinity in both PVE and PVP, it lacks defined Roles. Speced a certain way, almost all classes are decent at everything. Leaving little room for strategy or team work. Just pick something and go Offense or Defense. I enjoyed it for the most part, but I didn't approach it as an RPG, more of an Esport like a FPS.
Considering they have a Druid class and most likely more on the way, I'd guess Support will be part of everything and those without it will suffer. But a team with a Druid isn't going to have 5x the HPs as anyone else simply because they can spam heals till their finger falls off.