My best guess is that there's just a lot more they want to do with the current game, that they cannot do with an overhaul to the system, which would require them to rework the current maps and stuff?
Overall it's probably just money, but I'm hoping that it'll be a good sequel. I can't complain as I bought the game for half price, as Steam does a good job putting popular things at a discounted price now and then.
I just hope they don't focus on graphics and and other unnecessary factors, rather than focus on good, fun, core gameplay.
Found this official trailer:
http://ve3d.ign.com/videos/play/51516/P ... lash-Video
