I think it's a fantastic idea. Opening an exclusive to a broader audience allows more popularity, more sales, and more fun. My PC can't run much more the Left 4 Dead 2, so getting the opportunity to experience groundshaking technology on a platform that can handle intense capabilities is exciting.
To all of you PC elitists (Yes, if you're saying that it should be PC only because it will spoil the game or the graphics won't be as good otherwise, you are elitist) why don't you shove off for a little while? Your experience of the game won't be changed at all, and console-gamers will get to have fun. Are you so very arrogant that you'll cry out when people who don't have the money to blow on an outrageous computer get a treat?
As for the "FPS are dumbed down on consoles" argument, as someone who has played (and plays) both on the PC and my Xbox, I can say that you are wrong, and you are wrong hard. While the ability to hotkey commands and weapons is always nice, it's not like that's a core element of the game - the keyboard and mouse controls offer a wider variety of control schemes, but that does not make it superior. Personally, I handle analog sticks far better than a mouse - and unlike the mouse, I don't have to pick up my stick, move it to the opposite side, and then drag it over again to turn around. Outstanding.