Originally Posted by corporateslave

I personally read this as a positive change.
Instead of AA explicitly prohibiting the service for itineraries on other carriers, now it is up to the agent's discretion. This means they could "approve" a five star reservation for service with another airline they might not be able to in the past.

Of course this doesn't guarantee that they will approve anything, just that AA isn't blocking them from doing so.
I agree that the service should be extended to other airlines if connecting to/from an AA flight and you pay for it, but logistically this could be expensive/difficult in airports with several terminals that are often far away from each other.
Moreover, AA agents will have no clout with another airline's staff so they can't help you skip the check-in or security lines, or get you into the lounge, so it doesn't make much sense for them to help beyond the scope of their "power." With the new rule change the agent can better judge (based on your itinerary and their capability) whether they can actually help you or provide you with services you expect from five star, this means better service.