The prison stuff was a very important part of the story. The Czech and Polish soldiers gave up everything, job, family, friends, home, dog, girlfriend, life, etc, in order to help the Allies fight the Nazis, and free their homelands. But when it was clear Hitler would be defeated, the US and UK wimped out and let Stalin take control of their home countries. So after all their sacrifice and bravery, these heroes went home to be treated as traitors, sentenced to death or imprisoned under the harshest possible conditions by the Soviet puppet governments. Those who survived weren't freed until the 1950's, and even then some of them still suffered for their wartime deeds. It was a tragedy and to leave it out of the story would have been a disservice to the memory of these men.
As for the love story, it might have been overplayed, but it is true that there are many foreign soldiers who fell in love with English women during the war. Quite a few of them married local women and settled in England.
As for LW kicking ass, let's check the scoreboard: Allies 1 Nazis 0
