I think you're right, it was probably her best role, eventhough she didn't like it at all. That's sometimes the thing with actors though, they're so busy with their 'craft', that they forget to do what they're great at(Alexis Bledel is another example, she has an almost Woody Allen-esque quality to play light-hearted neurotics, but wanted to be more serious, which stalled her career too). Izzie Stevens was quite an ideal balance of comedy, drama, and personality for Katherine Heigl.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.