On the topic of Pandaren subraces, I think a mountain Pandaren would work. It's basically the red fur variants, but these could maybe be expanded on more, different tail lengths and ringtail patterns.
Also, random thought of something I would love to see is Pandaren Druids. I see them as a type of Monk who channels power differently and shape shifts into the forms of Xuen(feral), Niazou(guardian), Chiji(resto) and Yulon(balance).