Even Hoglan has his own blast beat. The role of a drummer might not be that different between genres but I don't think that means all drummers are interchangeable. I've followed Pete since the 80's, he's always played extreme metal and death metal, he's never played thrash but I doubt it's because he can't. Seeing him behind the kit of Slayer would be like the first time seeing Lomardo behind the kit for ST, he can do it and do it well but he doesn't look the part. I'm sure people would get used to him behind the kit of Slayer if it happened but when he's asked a stupid question it's easier to respond that his blast beats are different to what Slayer require.