Mission Editor/Maker???

I remember getting a shot of Infamous 2's map editor and I found it quite good and thought it added much more depth. I just thought to myself "Why don't Ubisoft do this?" I mean I reckon it would have it's advantages and disadvantages but it might be good as a little free DLC or at leats like an 800 MSP or like £5($8?). It could let you use any of the 4 console games' engine as a base for those feeling nostalgic XD. Any thoughts?