Mine would be a much larger collections library. Having come to go from Java and finding that the standard go library has no trees, no stack, no skip list, etc. was quite a surprise. Possibly the advent of generics will stimulate development of a more robust standard collections library.
It does have a doubly-linked list which can easily serve as a stack, though. And it has a heap which is a poor man's replacement for some uses of tree. I've found that I can get quite a bit farther with the built-in Go slices, maps, and lists than I thought.
But yeah. Now that generics are in, I do hope they add a handful of common collections.
