A simple sphincter at the top of the neck would suffice, methinks. We'll have to add a gullet with which to masticate, but that should solve the food problem. Retract the tongue down the throat slightly, and we can still taste our food, too. The same sphincter can also regulate air flow. With that, we have successfully done away with the human head.
Blind people do well enough without seeing.
We can do without those, too. So the physical arguments are dealt with. Of course, without eyes and ears mere recognition of another person becomes a bit of a chore. We have reduced the number of senses by two. This means we have only touch, smell, and taste at our disposal.