Setting aside nationalism, I'd say good vs evil, war and death are simply common themes in legend and story since the beginning of time. Death and some concept of evil are universal to all cultures. War I suppose is a little more debatable but I think you'd be hard-pressed to find a culture that didn't have many myths and stories involving some form of war as well. These things appeal to (at least many of) us as humans, they don't need to be subliminally introduced.
Anyway, it's a Marvel property so the amount of actual death is likely to be quite low, and the majority of the conflict is likely to take place on the scale of personal combat. With a couple of notable exceptions, Marvel films usually specialize in excessive property damage, not slaughter. I fully expect hundreds of "bad guys" to die in a variety of entertaining ways in Expendables 2.
I'm a bit hard pressed for time otherwise I'd love to debate this with you. You say that war, death etc have been common themes in human life since the dawn of time. That being said, I'd like to think that the human race has evolved expotentially over the years, in form and mind. We are more intelligent beings then we have been, we are no longer neanderthals and we no longer have to kill or maim to get ahead of life. We should be able to sit and talk like respectable intellectual human beings. Not, oh lets just blow the crap out of a country until it yields so we can put our own man in charge. See Eygypt and Libya for recent examples.
Propaganda is a very old tool. Rhetoric from the people in charge, the elite, has forced countries into illegal wars and battles for hundreds if not thousands of years.
When I refer to subliminally introduced messages I don't mean what you see on the face of things. Take Call of Duty for example. I haven't had the 'pleasure' of playing it but I understand that the main plot is the US in a war against Iran. Which is what Isreal are currently attempting to convince the U.S and NATO to engage in, in the real world.