Long story short, I don’t like it. However it needs a bit more attention than this, but I really don’t know where to start so I’ll just spill my beans. It will probably come out all jumbled and a mess, but whatever.
So the biggest thing right now is anything using celestial + battle sigil + strength runes. You can achieve 9 stacks of might for about 35 seconds just by consistently weapon swapping. The most common spec that uses this concept is the D/D ele. Assuming an average cast time of about 0.6 on weapon skills + attunement swapping, you can achieve around 458 healing per second. Considering there are rumors that you can get this value up to 600 h/s with lighting whip spam, I consider this estimate reasonable. On top of this h/s, you have Soothing mist and regeneration boon to top out your independent healing at around 797 h/s. On top of this, you also have access to things like water attunement swapping, cleansing wave, evasive arcana, and cone of cold for more burst healing. On a negative aspect to the spec, they only have 2.3k armor, but they have 18k health. By comparison, a bunker guard gets about 3k armor and 15k health. The low armor value of the ele is compensated, however, through their easy access to generate protection. Also if you notice, the standard d/d ele carries a doom sigil.
Let’s take a typical necro poison. Without any might stacks condition damage sits around 1.4k (about 200 condi dmg less than 15 stacks of might on a d/d ele), the poison damage on necro is 224/s. A D/D ele has around 797 h/s. With poison on them, they heal for 302 instead, and if regen boon is removed, a poisoned ele will heal for around 155 h/s. There is a cliffside drop from near 800 h/s to 300-150 h/s. This should tell the reason why Doom Sigils are so mandatory in the meta right now.
On top of this, as stated, D/D eles are able to achieve 9 stacks of might for 35 seconds just by attunement swapping. It is very easy for them to achieve 15 stacks of might through the use of just 2 blast finishers (each lasting 35 seconds).
Overall, this single build means you are ether forced to out-sustain them (through the use of poison and/or tankier comps), and/or have some sort of boon removal in your team composition. Necros are popular for this reason. Guardians are also becoming unpopular because of this, and similar, ele builds.
One of the main roles of bunker guard was to provide strategical might stacks when the team needed them. The best of the best would co-ordinate these temporary stacks with a spike. Now, however, the teamfight classes can do this independently. D/D in particular can even provide aoe burst healing (another reason to bring a guardian) – something that a warrior cannot do. The difference between a d/d ele doing it and a guardian, however, is the range associated with the two classes and the amount of healing. It a lot easier to provide burst healing via guardian than it is on D/D ele, but the ele has limited reasons to need healing from a guardian. Its also important to note the CC on D/D ele is more restrictive than the CC burst of a Warrior.
Overall, support Guardians are now becoming less and less favored. In its place, less co-ordination is needed to provide might stacks as everyone can do it more independently now.
Next we have the burst support classes: Mesmer, Fresh-air Ele, and Longbow Power Ranger. Traditionally, we see this role played most commonly by mesmers. Their effective range allows them to pick out a random target and co-ordinate with the rest of their team a burst on said target. These classes usually provide very large amount of vulnerability stacks for the sacrifice of less damage as they are ranged classes which can rely on good positioning and proper peeling to make sure they don’t get punched in the face (hello run-on sentence). Again, this damage requires a co-ordinated burst to pull things off most effectively and is a major reason why they have such easy access to vulnerability. Basically, if you ever played the cheese spec ranger spike in GW1, you know what I’m talking about in terms of potential random spike damage.