Ubuntu 16.04 Chinese font has seemed a bit odd to me since Day 1, but I probably have got used to it. I didn’t quite realize it until Graham Ou’s answer on Quora pointed it out, that I have been reading the Japanese version of the same characters. Here’s how you should change it.
Have you recently (re)installed your Ubuntu desktop? Your fcitx Chinese input somehow doesn’t work, does it? Here’s the solution: patch to the Sublime Text 3 for Chinese fcitx input. Tested on Ubunt 14.04 and 16.04.1 LTS.