I don't suppose the auto-attack can be bound to a mouse button? 'Cause, you know, that would be fixing what is really broken about it. AA by mouse click in the first two games works great.....why they decided to get rid of it is anyone's guess. "Because reasons" just doesn't cut it. 
One of the reasons is because of the way combat movement works in DAI. Archers are the only spec that has combat movement, everyone else must remain stationary while doing a basic attack. There also seems to be a lag between finishing the previous swing or attack and the time when movement is allowed, making the movement seem unresponsive and sluggish (and frustrating) at times.
Even after all this time I still have issues because I will be holding the attack key (left mouse), and also holding a movement key. The game has attack take priority, so I will be standing and swinging at air while my brain is saying that I should be moving (because I'm holding the movement key).
When you use the auto-attack function to lock on a target, the PC or NPC follows the target in shimmy steps and will only continue attacking after the target has stopped moving and they are able to do so again.
Since the original release of the game, they have added a few different hotkeys:
* Walk (Toggle)
* Auto-Attack (SP) [this is a toggle function, unlike the Basic Attack, which is a hold function]
* Toggle Mouse Look
* Sheathe/Unsheathe Weapon
Note that the auto-attack does not apply to multi-player. But no matter how many hotkeys they add, movement will never be completely fluid in this game because it was not designed that way.