Compared to most MMO's the pet hotbar is very lacking in functionality.
For that reason I am writing a list of what I'd like to see added in terms of UI.

- Pet hotbar buttons should be customizable.
Players should be able to drag the pet abilities into different slots, thus re-organizing it to their style.

- Right clicking on a button should enable/disable pet's auto use of that spell when obey is active. This functionality is present in games like WoW in which a dashed box appears around those buttons which are enabled.

- Pet Hotbar keybinds
CTRL 1 - 9 should be the default keybinds for the pet hotbar. Players should able to quickly set their pet to attack, or act passive based on these keybinds.

- Pet hotbar order
The standard layout for most MMO's for pets is similar to the following
Attack, Passive, Ability 1 - 4, Desummon