These are complex but interesting questions. First, yes I aggree a definition of domestic violence should be expanded to include other forms of abuse (e.g. sexual and psychological aggression, neglect, etc.). There is also the fact that domestic abuse should be not be considered a problem of male aggression to women only, but rather include both genders as possible perpetrators and victims for a number of reasons. Second, there has been recent research suggesting psychological aggression is as deleterious (in some cases more than) as physical aggression. It has also been found that psychological aggression precedes physical aggression in the family or with a partner and that they tend to co-exist. Further distinctions upon different types of victims and perpetrators (e.g. Johnson's typology) make the above evident.

I have just written around 5000 words for my thesis on different definitions for IPV, how they have evolve, the polarised debates around feminist conceptualisations etc - there are stacks of stuff out there on this, I have to say this is a very academic debate. I would argue that there is much more value in concentrating on how to work with perpetrators and survivors and affected children more effectively.