First off, why are the only categories Technical Support and Bug Report for the forum? It feels odd that there is no areas for discussion.
With that I feel like communication is very lacking in the game, outside of guilds there is no way to message anyone, not even Battle.net friends, in game, there isn’t even a friends list for the game. There is no way to do friendly matches to test things with friends and I can’t invite specific people to my Guild, I have to make them go out of their way to find it. These feel like very basic social functionality that’s missing from the game.