I would argue that the select is the more important feature. Goroutines are just lightweight threads, and go isn't the first language to have them.
No generics suck, unfortunately. I don't care that most things aren't expressions, and tbh, I don't know a lot of people that do. System-depdendent int is not a problem for me, but I recognize that it is a problem in some fields. I like how interfaces are designed and used in the language, so I don't share your opinion there. For the time package, the only thing that's badly designed is the American-centric parsing system. Everything else is, for me, ahead of the various package I've used in other languages.
The fact that duration is basically an int wrapper around nanoseconds, and converting between different units is very awkward are just the beginning. Take a look at Joda time (JVM, which served as the basis of what later was integrated into the standard lib) or Noda time (.NET) to see examples of properly designed time libraries. It's no wonder that golang's badly designed time library caused an outage at cloudflare.
No generics suck, unfortunately. I don't care that most things aren't expressions, and tbh, I don't know a lot of people that do. System-depdendent int is not a problem for me, but I recognize that it is a problem in some fields. I like how interfaces are designed and used in the language, so I don't share your opinion there. For the time package, the only thing that's badly designed is the American-centric parsing system. Everything else is, for me, ahead of the various package I've used in other languages.