The reason is that there is no theoretical skill cap in GW2. A full dps character can mitigate all incoming damage through dodging, positioning, blinding, blocking, or any number of momentary invulnerability mechanics. This means that, at best, the most skilled player will take no damage in gear that maximizes his damage output. We can refer to this player as the perfect player.
Now, most players are nowhere near the perfect player. They get hit by things, and those things hurt. Whether it is GL’s poison projectile of destiny, Subject Alpha’s spells, the Fractal Grawl boss’s arrow, or what-have-you. In those cases, where the player is less than perfect, they will suffer damage. In some instances, like most dungeons, a few hits like that doesn’t kill a player and they can offset it with their healing. In some instances those hits will hurt a lot. If these players take enough hits and get downed, their dps will no longer matter, as now they are down. If they are defeated, their dps drops to 0. In both cases, they are a burden to their team.
What the player does when he takes things like Vitality or Toughness or Healing Power as a stat is take insurance against these cases. He is counterbalancing his own skill against the likelihood that he will take hits and go downed, thus becoming less useful. There are some cases where taking a defensive stat is beneficial to offensive classes… Some cases I can think of offhand are:
- High Toughness makes you more likely to be the target of aggro, making Knights valuable for bulkier classes or players talented at damage mitigation.
- High Toughness sometimes translates into better offense through rune bonuses like the superior Undead rune’s 6th bonus.
- In WvW, where your enemies are smarter, don’t rely on AI, target you specifically, and it is essentially impossible to fully mitigate all damage, it is valuable to have enough Vit/Tou to mitigate specific types of bursts and counteract with your own offense.
Note that Healing Power en masse is a generally inferior stat, but has merit in small doses. Its uses are incredibly build-specific, and are essentially focused on improving your sustainability against certain foes, rather than your ability to mitigate damage. Basically, you only care about healing if you assume that you have suffered damage to begin with.
These support roles are still valuable in PvE and high-end content like dungeons and fractals, they are just not something you want 5 of on one team. A support Guardian has a lot of value and team-wide damage mitigation. 4 full Berserker players have a much easier time maintaining their optimal range against high dps enemies that have difficult-to-mitigate attacks when they are supported by something like a Guardian. Furthermore, some support roles are offensive support, such as Time Warp on a Mesmer. These roles are invaluable, and critical to success in many instances. Certain explorable paths vary in what is the best way to tackle them, and using what classes.
For instance, I use a Guardian build that many might laugh at me for on the forums, but everyone praises me for in-game. I can maintain a party-wide 15 stacks of Might permanently, permanent Protection, permanent Swiftness, permanent Regeneration, party-wide Aegis every half-minute or so, innumerable reflects and absorbs that mitigate damage, and more. My team can face-tank many enemies that it otherwise wouldn’t be able to thanks to my support. This support improves the net dps of the team because while I do less damage, the dps members of my team no longer need to waste time and dps doing things like dodging frequently, getting out of aoes, or use their healing skills. My support improves the dps of the team. That is the key I want you to take away from this.
tl;dr: Support is good in moderate doses, and well-played support targeted for a specific instance improves the efficiency of teams substantially. Do not let yourself think that “support is bad” because that is wrong. Just make sure you understand how to make support good, ignore those who cry havoc, and run the end-game like a boss.
