In my point of view, the PS3 is mighty enough to run TG2, I doubt that most users of a PS3 will be patient enough on the other hand.
In 1988 I was laughing at friends using such a silly device like a mouse as I assumed to be faster with keyboard shortcuts ( most times I am) and a joystick. But what I learned a few years later is - not do underestimate the capabilities of an input device and its ongoing developments (just thinking of the controllers of the Wii and the controllerless input of the XBox).
Besides of this many people using a PS and its pad are capable to do amazing stuff by using different combinations of buttons and so on ... I have Stephen Hawkins in mind ... in his wheelchair doing all this complex maths using a joystick ... if he had a the capability to use a modern pad and the time for TG2, I bet he would be faster than any other of us, using the GUI. ,-)
At least for me ... most time developing scenes (I do not say rendering) in TG2 is moving my mouse, either to swap from one gtoup to another, selecting nodes, going to a special tab, zooming in the node network and so on ... Having a joystick to navigate through the groups and nodes could be fun

Regards,
Volker