After reading some of the threads I can totally understand about the dilution a new forum would create. So, I think it's a good ideal to not open a Travel forum up.
I must say that travel photography, to me, is about capturing the essence of the location. What makes it tick? Where do locals go and do? What makes that location great? A photo of me by the Eiffel Tower does not create compelling photography nor does it make anybody want to go there.
The number one comment I get from visitors to my website or friends is that the photos create a compelling wish or desire to visit. I've compelled at least 10 of my direct friends to travel to Argentina. That is travel photography.
Does it need it's own forum, maybe not but good travel photography is about capturing the vibe of the city on film.
Loren