You still need a Makefile if you use things like godep, or their new `go generate` stuff.
They have a long way to go on tooling; however, getting to say that is a luxury, due to just how "right" golang has been for systems work. Golang has been amazing to work with, and has just been stupidly productive. I miss debugging (gdb) and generic compile tools like tup, but that's about it!