This is where I don't say what I've heard because people would be mad at the messenger. But I will say that it's been indicated to me that the complaints at GDC about system memory amounts was being directed at a specific platform holder. And you'll probably find out about things much sooner than you think.
It wasn't created by the people making those roadmaps. It was a marketing thing, If I remember correctly. Also, it was before the system was delayed, which happened some time in 2011, I think after Kinect goosed 360 sales back up.
Also, here's a fun fact: people are currently playing a game that was originally contracted as a next-gen exclusive, and have been for a while. That's all you get out of me.