I don't think that's a good idea. There are lots of ways for people to identify where you are at. That would be like saying remove mic ability. Its crazy to think those with mics aren't telling people where you are.
I think the dual log in option was a good thing the developers included.
The more mobile you are the less likely someone will track you down and kill you.
there is a big defferance from split screen and working as a team with your mic. I like the split screen ideal but its not needed in hardcore. they limit other game modes with only game chat and in black ops they had game modes that didn't let you have split screen in them. Thats what i am say the keep split screen where it belongs in core game modes not hardcore