Saying Carnage is one dimensional is like saying Joker is one dimensional. Read the Mind Bomb or Its a Wonderful Life one shots and tell me hes one dimensional. I broke my self imposed exile on the Spidey books(since OMD) for this and wasnt very happy. This book so far doesnt really even have Carnage in it. Carnage is more than red alien goo, he is the serial killer Cletus Cassidy. It is that twisted man under the symbiot that makes the character. A character that is totally evil because he has taken his nihilism and anarchism to its logical ends.
I was happy to see Shriek and Doppleganger again, just for old times sake, but a Carnage mini that doesnt really have Carnage in it is dissapointing.
Good analogy to joker. With a good writer, carnage can be so much more than a killing machine.