While the lack of information, even when there is no information, is maddening and AA acknowledges this in its CSP. If all AA can do is say that it has no further information, that is all there is. But, it is better to make that announcement than none at all.

All of that said, I tend to be proactive. I've got reroutes in mind and then am in line and on the phone, arranging a reroute based on specific requests. GA tend to look at getting you to DFW, but that is a connection point for you, so all you are looking at is YYC-LHR on any carriers with which AA has an interline ticketing agreement. When you can feed an agent a series of flight numbers that he can type in, you are much more likely to get what you want.

AA is also willing to, but prefers not to, issue paper tickets/FIMS's. When you are rebooked onto another carrier, a paper ticket/FIM can be worth its weight in gold as you may walk straight to the gate for your other flight and present your new ticket without having to worry that the space is there, but you are in the ticketing queue while your new flight pushes from the gate.