Why? I'm not saying go is a bad language at all, it has a lot of good points, as outlined in the source of this discussion. It is however not a perfect language and as such, it never hurts to criticize it, if only in the hope that it will improve in the future. I personally find the mental model required for go quite abrasive, but that's only me, and I won't hold it as valid criticism.
The alternatives vary according to the issue you want to tackle, so I would be hard pressed to recommend a particular one. And go does fill some vacant spots in language space.
That's the problem, I see the following often suggested instead of Go:
Java - maybe if you use Spring Boot you can get around some of the boilerplate, but there is a ton of baggage in the ecosystem.
Clojure - This is really popular where I work but LISP + Java Ecosystem turn a lot of people off. Also, some people really want static typing (maybe Spec is good enough?)
Node/TypeScript - terrible concurrency, good for throwing something together that works rather quickly, good for cutting corners. Terrible memory, cpu profiling. As a professional node developer in the day job I could go on and on, but at least the type system is better than Go (too bad the concurrency story is so abysmal)
Elixir - not popular, but at least it's on BEAM VM and has lots of libraries. Not statically typed (yes you can use dialyzer). Never done anything with it, but apparently deployment is a pain.
I personally write JavaScript mostly because its ubiquity. It's good enough, until it's not.
The alternatives vary according to the issue you want to tackle, so I would be hard pressed to recommend a particular one. And go does fill some vacant spots in language space.