10-15 years from now it's likely Go will have all the features that people have been asking for.

If this hapoens, the entry bar will be high again. The tooling will get slow, and runtime will become more complex.

To me, Go is all about that simplicity that comes with the lack of features. Though I think it can probably provide a little more in terms of generics, it also has to be careful not to become Nim or D.