Been a while since I've used a hunter and I've got brainfuzz going on, but if you have automatically melee disabled, doesn't IWT move them in range against attackable targets without letting them run all the way up into melee mode?

Either way, I have run with a mixed ranged&melee group, it's no different than leaving your healer at range. As a matter of fact, it was kinda nice in some situations, like Ionar in HoL. I could send 1 of my melee guys to follow my healer and the other to follow my hunter to lessen issues with AOE damage across the team.