WW2 casualties 

I think some more narrative prose is a good idea. The main tables should still be there for easy lookup, but the topic is complex, often controversial, and different sources have different numbers. And all this could/should be elaborated on and explained in the article, yes. Many people will come to the page with numbers on their "own" country that they have learned or read, and we should have some text explaining more thorowly what the numbers we list include. And that's probably best done outside tables and in addition to just simple footnotes.

Maybe we could also have separate casuality sections for the different (major) countries, with text and tables where there could be made room for lower and upper bounds on numbers and space for citing different sources and their numbers. Not so much that I expect you to find and look up every different estimate, but there are many people editing and there could be a value in having room for those comming here later with different sources to add to the information. I don't know.

But I really like your work so far. It was about time that we got some well-sourced numbers in this article. Well done!