1) No immutable types. My work team is a huge user of immutable data stuctures in Java to make sure data passed around to other teams isn't changed. Go doesn't really have a good way to do this.
2) Refactoring can be really annoying (or at least really noisy) because of public/private being defined by capitalization of method/field names.
3) Error handling isn't great. I love Go's errors being just normal values, but the `error` interface is awkward when trying to figure out what kind of errors can be thrown without having in-depth knowledge of the kinds of errors that can be returned. We regularly need to make different decisions depending on the kind of error returned. Knowing which errors can be returned in Go is not defined by the method being called (only in comments).
