Sure generic's would be nice, but I do not feel they really would change much. After using and supporting Go for years, I would rather keep it how it is. Simple and verbose.
Getting up at 3am in the morning to respond to a page going off in a production system that you didn't write, there is something extremely parseable with Go. It doesn't hide and abstract things in a way where you have to end up digging.
Often the docs are just not enough to really understand software. In the event you end up having to go read the code to understand it, when things get that far, I wish it was Go every time. There is little in the world more frustrating than having to read 18 java files to understand a simple format of a payload because your coming in late to the codebase.