Right, but say if I'm a caster and I got agro, there's no tank to taunt it off me. I take it each class has a sort of evasive type of play to them? I've seen it with thief (thief tanking is always cool). Again, it's just strange to see no trinity involved. It's new and refreshing to see.
Every class has access to dodge for evading attacks, and a self-heal for when things go wrong. Casters aren't getting one-shotted exclusively; we've seen footage of heavy-armored warriors and guardians getting splattered as a reward for their inattention as well. Players need to keep their eyes open to enemy telegraphing and what's happening around them.
Additionally, every class has access to elements of Control, GW2's replacement for tanking. Elementalists, for example can Chill enemies (causing a 66% movement speed and skill cooldown reduction) on
every single weapon except scepters, simply by shifting to Water Attunment. And because the Scepter is a main-hand only weapon, it would be paired with either a dagger or focus, both of which have an ability that chills. Air attunement has either a knockback or a stun on all but one weapon setup (Scepter / Dagger, though scepter does offer a Blind which negates the enemy's next attack). Earth Attunement has a lot of cripples (50% movement speed reduction) and immobilizes, plus two Shield spells (one that greatly improves armor and one that renders the caster invulnerable for 4 seconds). That's not even mentioning utility skills like Arcane Shield (Block attacks with an energy shield. If it blocks three attacks, it explodes), Lightning Flash (teleport to target area) or Mist Form (Morph into an invulnerable, vaporous mist for a brief time). They can also use Conjure Earth to create a "Magnetic Shield", which acts like a new weapon, giving the elementalist 5 new skills (including a cripple, an interrupt and an invulnerability). Oh, and when you create a Magnetic Shield, you automatically equip one and one is conjured for any other player to pick up. That means if something goes wrong,
two people can step in and work to control the enemy while the 'dedicated tank' (which doesn't exist but for the sake of your scenario we'll include) rallies, with the help of the other group members reviving him and his own downed abilities. Worth mentioning that the Magnetic Shield has a force pull, so an Elementalist 'tank' can yank an enemy away from someone trying to rally.
And if you're still downed after all of that? Elementalists can immobilize foes and assume a mobile, vaporous form while in the downed state.
This doesn't even touch on all of the other Control abilities that everyone in your group brings with them. The difference between a good player and a dead one is situational awareness and knowing what skills to use and when. Success is placed entirely on the individual, not the tank or healer. Some people are going to be pissed off that they can't blame someone else for their failures, but guess what? Those people are assholes and we don't care what they think.
Probably a really dumb question, but the way I read this is the beta is over Saturday night / Sunday morning (Sunday at midnight) rather than ending Sunday night / Monday morning. Is that right?
Not a dumb question at all. The Beta is supposed to run for 60 hours and start at noon Pacific time on Friday. That means it will likely end around midnight on Sunday. For east coasters, it will run from 3PM Friday to 3am Monday morning.