I disagree with the initial posters tone strongly, BFC has done an amazing job overall. I also think the basic game mechanics have reached the stage where either a whole bunch of AI programming options, or better multi-player has to be the next big focus. The basic simulation works now, it can always be improved, but it works.
AI and better multi-player now the single largest holes in the game experience. I really think they need to be pushed towards the very front of the admittedly endless list of desired improvements.