I don't think we should unite all Martial Arts but I think we should try and help unite the people of the Martial Arts. That being said I would have to say in my experience with in the Arts today this is already happening on a large scale. There is only a minority that don't appreciate and accept different Arts. These people that won't or can't accept the difference's with in the Arts in my opinion, aren't really worth getting yourself worked up over.
Just my opinion