I already pre-ordered it a month ago, when I still had money. Amazon has become a good friend of mine recently.
About the lack of split-screen; there was an interview recently where they said they did get it to work but it came too late in the build's process to include it. For the love of god HVS, license your engine out!
The proximity voice chat is a smart idea in my book. It clearly shows they thought about instead of just tacting it on. I wonder if they'll have a "shout" mechanic though like in Halo.