Go having nil for various types is indeed a problem.
In fact, a few weeks ago I caught an issue where a map in Go was unexpectedly nil when it should have been full of data (missing initializer), and I caught it because the serialized data was then consumed by the client written in Swift which doesn’t have this issue. Go thought it was writing data to spec but the client immediately diagnosed it as having an unexpected null before it even tried to work with the data.
In fact, a few weeks ago I caught an issue where a map in Go was unexpectedly nil when it should have been full of data (missing initializer), and I caught it because the serialized data was then consumed by the client written in Swift which doesn’t have this issue. Go thought it was writing data to spec but the client immediately diagnosed it as having an unexpected null before it even tried to work with the data.