How soon people forget, there was a time when the thought of playing an FPS on a console with a controller was laughable.  The prevailing opinion was that FPSs couldn't only be played properly by a keyboard and mouse.

WoW on Kinect huh...No doubt the 360 could run it's vastly antiquated graphics interface.

My only concern is how the Kinect would capture player movement. Playing as a Hunter, there are times when I have to run away from an enemy or enemy player, jump, spin 360, and shoot them. Same would go when I was kiting mobs around a frost trap during 10 man Naxx in Wrath.

As for PvP and Arena, just imagine Kinect trying to capture the movement of a highly rated warrior or melee class who runs circles around an opposing player blocking their line of sight so that they cannot get off any spells on the warr or melee class.

How would Kinect detect when the player playing as a Rogue goes into stealth? How about a mount or flying mount?

I have no doubt Kinect could work with the most basic of movements, but once you get into the more skill stuff then this is where I go O RLY?

The regular d-pad wouldn't work for FPS too well but then the analog stick made it more reasonable to play FPS on home consoles (N64 Goldeneye pretty much made FPS acceptable on home console systems).  Keyboard and mouse are still superior.  After playing CoD:WaW and Black Ops on Wii, I view regular controllers (analog) as inferior for FPS on home consoles.  Wiimote aiming allows me to aim with ease anywhere I want to on the screen.

How soon people forget, there was a time when the thought of playing an FPS on a console with a controller was laughable.  The prevailing opinion was that FPSs couldn't only be played properly by a keyboard and mouse.

Obviously some people still feel that consoles can't match playing an FPS on a PC with keyboard and mouse, but it doesn't negate the fact that the genre is extremely capable of being played by a controller when the game is designed for it. 

I'm not saying an FPS is the ideal genre for Kinect alone, but a hybrid control scheme could end up being the best method yet for playing one. 

All I'm saying is I think it's too early to discount anything yet.  We've seen what hackers and hobbiests have accomplished in less than 2 months, I think experienced developers can bring a whole lot more to the table.