Tactics: Tanking in TERA

A common question that people ask is, how will tanking work in an action based Role-Playing Game (RPG)? In traditional style MMORPGs, as most of you know, it involves tanks that build threat, hate, enmity, whatever… using their attack and taunt skills. As a result of this, the mob focuses on that player, and in most situations, everyone else is pretty free to do as they please aside from dealing with positional Area-of-Effects (AoEs) or mob adds. TERA does have the traditional aggro and taunt systems, but what about special attack patterns, target switches and projectiles in an action combat system? What can you do beside relying on building and maintaining a numeric value?