>What sounds cool at the time because it's different and
>distinct is probably going to peg it with that era. Someone
>like Nas or Black Thought who have more or less a "normal"
>dope flow will survive the various trends.

^^ to this point, I think it'd be more accurate to say that BT and Nas are simply more versatile and able to change up their styles which results in their not being tied to any particular "gimmick" or era.