Interesting, though I'd have liked Lucy to be back as the sidekick this time around. Please don't make Shia his son. PLEASE GOD NO!
Chris Evans would be a good son for John McClane. He can act, do action and is a funny bastard to boot. If I were Chris Evans, I'd do Die Hard 5 for free just to say I was in the Die Hard universe, let alone for the opportunity to be McClane's badass son and work with Bruce Willis.
And setting it in Russia gives them the perfect excuse to reintroduce snow. Since Movieverse Russia is always buried under tons of snow. And everyone knows snow=Christmas and Christmas=Die Hard! It's brilliant!
It has to be R, though and filled with F-bombs, non-CGI blood splatter and brutal kills. The lack of the first two really stood out in Live Free or Die Hard.