I'd like to see the Interface system more powerful. You can already do some very un-gothonic things with map[string]interface{}. I'd like to be able to compose functions already based on an interface, to implicitly implement other types, rather than spelling out each function (maybe you can already, I'm still only a few months in to Go).
I liked the concept of "try" but I agree with the peanut gallery, the syntax needs work. But many gophers (it seems) agree there should be a shorthand for "I got an error, bubble it up to the caller" aka "if err != nil {return nil, err}"
Or maybe not. In some ways, the verbosity of err != nil everywhere makes me look for ways to solve problems with less error returning.