It isn't.
DAI's combat is fundamentally broken. There is an invisible radius around the player, and when an NPC party member leaves that radius their AI "breaks" and they leash back into it, removing all commands from the character. It's egregious when fighting against large bosses, like dragons, where you'll end up with party members leashing and running back to the player, in spite of everything. The large environments are not designed for the combat engine.
For example, it is impossible to have a player attacking at max range in front of an enemy, and a party member on the opposite side also attacking from max range; the NPC will leash back and break positioning. Because of this, any kind of advanced tactics are at best unreliable, and at worst impossible.
Comparing a fundamentally broken system to TW3's combat is an insult, regardless of what one thinks of the latter's quality.