Ok, glue dried, been playing FC4 for about 20 min, and no problems so far.

So I would say now there is a fix for when the plastic arm breaks, probably depends on where the break occurs. Mine was basically flush with the bottom of the thumb stick. Saved buying a new controller for the next little while anyway!! Hope this helped

Ok guys, just found that a thumb tack fits perfectly into the small hole on the plastic arm that holds the thumb stick to the control module. Filed the thumb tack off so I was left with the small steel pin, gorilla glue the pcs back using the thumb tack pin for reinforcement. Waiting for glue to set up well and see how long that lasts for. Maybe saved 80 bucks... maybe not: I try and post the results if I remember