I'm still unsure of your complaint. If they hadn't done something that allowed you to workaround a change, you'd be upset? It sounds like you want to complain about the change, even though they anticipated potential issues and included the trace flag.

As for SP1, that's a problem for sure. I think it's embarrassing and unfair for them to issue patches with fundamental problems. Clearly there should be major RCA analysis on how/why that happens with a goal of reducing the chances of that in the future. I commend them for reacting and responding quickly, which is more than some vendors do.