Charlie's intro on "BigFat" reminds me alot of the "jazzy" bridges that Neil does all the time on Rush's recent instrumentals, especially in "Where's My Thing".
Unfortunately, Anthrax's music kinda dictates that he play a certain style. It takes a great drummer to stand out on straight ahead 4/4 time and Charlie has done that time and again. I bet he would blow us away if allowed to play a different style or odd time signature.