If you're using a basic ranged attack (i.e., one that doesn't cost spirit), what I do is map the attack to a mouse button and a movement power (a dash of some kind) to another mouse button.
Then I hold one button to constantly attack and aim the boss while using the other to navigate. I have no idea how other people does it, tho.
As for DD's squishness, he gets a self heal eventually that is tied to his combo bar, so what I do as a rotation is attack with a basic until fill the combo bar, self-heal and when available use the signature.
DD's signature is one of the best AoE in the game and its cooldown gets cut every time you use something that consumes the combo bar, such as the self-heal I mentioned. Other very good AoE that has nothing to do with the combo bar, but I use regularly because it is godlike and has a short cooldown is the one where he throws his billy club to make it bounce around. When you add all of this: (bouncing billy club, signature, punching dudes, self-healing) it creates an AoE self-healing no-spirit-spender machine.
Then I hold one button to constantly attack and aim the boss while using the other to navigate. I have no idea how other people does it, tho.
As for DD's squishness, he gets a self heal eventually that is tied to his combo bar, so what I do as a rotation is attack with a basic until fill the combo bar, self-heal and when available use the signature.
DD's signature is one of the best AoE in the game and its cooldown gets cut every time you use something that consumes the combo bar, such as the self-heal I mentioned. Other very good AoE that has nothing to do with the combo bar, but I use regularly because it is godlike and has a short cooldown is the one where he throws his billy club to make it bounce around. When you add all of this: (bouncing billy club, signature, punching dudes, self-healing) it creates an AoE self-healing no-spirit-spender machine.