Where do you draw the line on how good human-machine interfaces should be? I'm sure this model could be a convenience for many, and while it may be social for some, I am not sure it would substitute existing human interaction for those users.

Besides, I do not think there is anything inherently immoral with not being social, or not having the ability to be. Consider for example people who do not naturally have the social network to interact with people they want to (e.g. some gifted children).

I am not convinced this model has enough empathy to satisfy most users on an emotional level. A bond is not merely an exchange of words, but prolonged and deep contemplation of the other being. We cannot introspect into these machines, and they certainly cannot yet do the same to us.