The number 4 is an unlucky number in China as it is sounds the same as death in their language. A few companies have skipped 4 in order to keep their China base. The more common one is to skip number 9 as it sounds like suffering in Japanese. The big ones for that are Windows and Apple with the iphone. It's just to keep the Asian market accessible.
The main gripe I have with Discord is the separation of voice and text channels. I just think it makes it clunky and not very intuitive. As long as Teamspeak stay true to their roots I don't think they can go far wrong.