When you said "a small set of features is bad if users cannot efficiently extend the language because the needed features aren't included" I assumed you meant

When you said "a small set of features is bad if users cannot efficiently extend the language because the needed features aren't included" I assumed you meant something like operator overloading or macros or compile-time templates like in other languages. It seems like I was misunderstanding you. If all you meant was "a small set of features is bad if users don't have generics", then yes, my earlier response was not appropriate. However, I would still have to disagree, given that I have written a lot of very useful code in Go, much of it quite reusable (without interface{} or reflection). I did go click on that link and started to watch the presentation, FWIW. It's too long for me to watch now, but it definitely looks interesting, so I'll try to watch it in the next couple days. Thanks for pointing it out to me.