Frank, I understand what you are saying when you write:
"I think that if a person attempts to "blend" with another by making their voice sound like theirs, they are in for vocal problems."
However, I think this is a case where you are substituting YOUR definition of 'blend' into what everyone else is saying. I don't believe anyone is talking about "making their voice sound" like someone else's. I was refering to 2 voices that sound good together. Nothing else, just sounding good. I think that's what everyone else is saying as well.
Therefore, given that definition, there are some people with whom it just goes together, like cake and ice cream. Others seem to be lactose intolerant.
Blues