Pandaria wasn't an unknown, and the Mogu and the Thunder King were all part of it. Pandaria was known and demanded by a lot of people for a very a long time.
Nightborne are just recolored Night Elves, one of the most popular races in WoW, hardly a risk. Additionally, they came out with 9 other races.
I'm not sure what that means that it's neither. Does that mean the race doesn't have a humanoid form outside of the Dracthyr form?
Did any of the leakers mention a revamp? I heard someone said SMC
You can customise both forms, like you do with worgens, but saying that humanoid is human? that's harsh. Depends how you will do it. Sadly, you cant be a dragon gnome.