Of special note is the introduction of the "role feature" that allows characters to take on specific class roles. The role features are set active outside of combat, but can be switched around as you would with traditional alt characters. So, for instance, a Fighter role feature is a weapon specialization role that allows you to play as a fighter with a variety of melee weapons. A Rogue role feature focuses on stealth, evades, and sneak attacks, as you might expect.
Read more about the Fighter and Rogue specialties and feats in this week's dev blog.
[Thanks to Chris for the tip!]