Information about Tanking is given @ 49:00 onwards...
Aggro Mechanic:Aggro depends on which attacker stands closest to the enemy. No specific skills for grabbing aggro. The closest attacker gets and holds aggro.
Resulting Playstyle:There's no tank per se. There's 3 armor types (light / medium / heavy); whilst heavy armor types will be more suitable for holding aggro, every class will have skills to mitigate incoming damage to a certain extent. Since there's no designated healer class, combat's gonna be all about moving in and out of aggro range and keeping one-self alive (and stepping in to keep others from dying). Likely a dodge roll will be enough to lose aggro to the next guy. Aggro transitions are likely to occur naturally. You get too much heat, you get the fuck out of there and heal back-up. Switching between melee and range weapons and skillsets depending on situation.
Should work great for PUB environment, as well as allow for higher difficulty encounters with much higher requirements at execution (f.e. split-second aggro transitions and managing key skill cooldowns). Taunt's overrated really, thinking about it.