Me saying I think that what you have listed is too much is just speculation. Like I said, no one really knows for sure what will be needed to run the game comfortably at relatively high settings and we won't know until the game is released. If you want to get the best bang for your buck then you'll have to wait until after the game is released(to be certain) or at least get some feedback on the beta version(for a closer estimate) to see what you'll need.
I can't really speak on sim city, but generally they tend to keep the specs somewhat low for those games. It's been a while since I've played, but the focus of that game is more on gameplay and not really eye candy.