Here, after over 50 hours of tweaking, I present to you my nearly perfect Steam Controller configuration.
I've made a comprehensive video guide on youtube at https://youtu.be/roymJc-QU5Y
Or you can just copy/paste the link here: steam://controllerconfig/681660/1399622674


Left Trigger: Dedicated Modifier -- Changes: Right Trigger => Right Click -- Changes: XYAB keys from 123 => RTY
Left Bumper: 180 turn
Right Trigger: [Full Pull] Left click -- [Soft Pull] Tab -- {Full Pull = Right Click while Left Trigger Held}
Right Bumper: [Quick Press] Jump -- [Long Press] Mount Ability
Start Button: [Quick Press] #1 Consumable -- [Long Press] #2 Consumable
Select Button: [Quick Press] Autorun -- [Long Press] Cancel Autorun
Left Grip: [Quick Press] Interact/Loot -- [Long Press] Escape
Right Grip: Stance Switch
Left Touch Pad: Non Stance Abilities -- {Menu and Mount Hotkeys while Right Trigger held}
Right Touch Pad: Mouse
Analog stick: Movement -- {Party Member targeting while Right Trigger held}
Analog click and hold in: {Mouse wheel on Right Touch Pad}
X Button: First combo starter -- {First combo extender while Left Trigger Held}
Y Button: Second combo starter -- {Second combo extender with Left Trigger Held}
B Button: Third combo starter -- {Third combo extender with Left Trigger Held}
A Button: Defensive/Dodge Ability