All mistakes are pretty massive, so I wouldn't be able to choose one.
About the always online thing: There are 76m 360s sold. There are 46m Xbox Live accounts. Why the fuck would MS want to lose 30m consumers out of the gate like that?
Either the rumours are false or they are incredibly stupid.
No troll is too much for me to handle. I rehabilitate trolls, I train people. I am the Troll Whisperer.