That if they want to do much, they need to release a NEW game. If they want to stay on both platforms and have the "same" game. The money is in the console, so we should just be happy as PC gamers that they are going to release ANOTHER game.
That's all well and good except L4D has been out for barely more than 6 months. It's simply waayy too soon for a sequel and given the general lack of content of the original L4D, this feels like a cheap way to milk the franchise. And Valve isn't exactly on the verge of bankruptcy so they don't need to put out a game every 6 months.