I just bought a Steam Controller, and started playing ROBLOX with it. I played around with configuring the controller, and it seems the best way to use it is to have the Analog Stick control the player’s movement and the Right Trackpad to control the mouse (this way, you don’t have to use the built-in selection system to fish around for the gui you want - you retain complete control of the mouse from the Gamepad).
This control scheme works flawlessly with the following exception:
The ROBLOX client can’t decide whether to display the mouse or the Gamepad’s dot cursor. The two literally fight for the screen when I am using the Trackpad to move the camera and the Stick to move the character simultaneously.
I think it would be great just to have a setting to disable the Gamepad’s cursor and leave the mouse in full control.