The discussion[0] on the golang-dev for this proposal is getting the most discussion out of of any of the proposed features. Most of it are people asking for addtions to the feature that would change/add-to the language syntax (which isn't allowed in Go 1.x) or changing the 'internal' directory name to something else.

[0] https://groups.google.com/forum/#!topic/golang-dev/_cAggq73y...