I was much the same at first, thinking that as I didn't know as much about the Eastern front I probably wouldn't enjoy the game as much as CMBO. Boy, was I wrong!
Since before I got the game I started reading a fair bit about it all and I think there is a certain terrible romantisism about the Eastern front,It's difficult to read accounts of Stalingrad, for example, without thinking something of the bravery of ordinary men an woman living and fighting in conditions that can truly be called horrific.
For me, I have gained more and more respect for those who fought and died in this war since buying the game. I even have a better understanding of the war in this theatre since buying it, and I thinks thats something pretty special for a computer game.