I don't like the idea of allowing KB/M use on consoles, because not everyone will use it, and will create a disadvantage. I prefer shooters on the PC, as I am just more natural with them, though still not great (but have really yet to play much in the way of FPSs since getting my Razer mouse, which has a lot more precision, not to mention on-the-fly sensitivity adjustments, worlds better than my standard optical mouse I had.
I've gotten better with consoles. Definitely improved with the 360 controller over the past two years, because I've played it with at my buddies, don't own one myself. With the Playstation controllers, specifically the PS3's, I've improved a lot. I'm comfortable with using it for shooters, but would still prefer a shooter on the PC. I don't own a single shooter for a console that has appeared on the PC.