I can see that you haven't listened to COB much. Let me fill you with some details. I think Jaska has some very creative and sometimes groovy stuff, with a little hints of jazz here and there. Follow The Reaper is the CD where it all began.
First of all he makes really nice use of his hi-hat on some fills, it is simple, but sounds really good - song Follow The Reaper at 3:04
The intro fill to Bodom After Midnight shows that he really has some imagination. This song also has some nice fills in triplets, and a great fill at 2:49.
On the song Punch Me I Bleed there are various fills that many jazzplayers use. For example at 2:17, and at the end of the song.
You can definitely see that he is fast also, for example in In Your Face, 32th notes in doublepedal starting at 3:20.
And in Next In Line a very fast fill at 1:40. Also check out the groovy stuff at starting at 3:14.
And finally, there is also a solo for you so you can see more of his creativity and imagination I told you above:
http://video.google.com/videoplay?docid=3305646172938024090&q=jaska+raatikainen