I understand that you do not want a bickering back and forth of what the traveler and owner say, but allowing the owner to have the last word give them much more credibility. We the traveler post our review, they counter and that's the end of it.
I recently gave a negative review to a hotel. The manager responded and what he is saying is just not true, what he says happened is not the case, but there it stands. Also 50 percent of his response is an advertisement for his hotel. This particular individual has responded to other negative reviews from other users in the past by blaming or accusing the traveler.
Maybe you should allow the traveler to post, the owner to respond and the traveler to have one additional short response. It seems to me, that the current system will discourage honest, negative reviews, because who really needs the hassle of being falsely called a liar online.
I appreciate your time and would love to hear from other posters with their thoughts.