AMD's graphics card division wasn't particularly great when he was heading it, and seems to be doing a lot better now that he's been gone a few years.
Since he left, the energy efficiency of AMD's graphics cards has more than doubled, and their new cards will be competing at the enthusiast level against Nvidia's best offerings again, rather than only having more mid-range models drawing over 50% more power than the competition, as was the case when he was heading Radeon. He might be better than whoever Intel had in charge of their graphics hardware before, but I'm not convinced AMD is at much of a loss without him.