Should I avoid downcasting by any means when using factory pattern?

http://en.wikipedia.org/wiki/Circle-ellipse_problem is your 1st example of evil. If you see that you can do something with violation of base principles, then you should invent another wheel or try another hat: http://en.wikipedia.org/wiki/Six_Thinking_Hats.

Downcasting, especially in a factory pattern implementation, makes pretty good sense to me. It actually flows well with the "program to the interface" ideology. Not sure why people feel that downcasting is bad.

Check out contravariance as this is what you are looking at.

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.