I really don't think generics (or contracts) will benefit the language. Most people who miss it are just missing the collection frameworks from Java/C#, and there are solutions to this anyway. (go:generate being one of them if you really need collections for X types).

I did miss generics when I first started writing Go, but after doing so for about a year at work and 2 years before that, I don't find me missing them at all.