Found this rather interesting interview with Grant Collier on CoD4.
http://www.youtube.com/watch?v=qMfTR8PBrsE
From what I have read he is no longer at IW. Wonder if he didn't like the direction MW2 was going and jumped ship. I wouldn't doubt it myself, as he sounds like he knows what makes a pc game good.
Activision reassigned him. He was the one pushing for free map packs on all three platforms, too.