This post by Russ Cox (a co-inventor of Go) describes leaving parametric polymorphism out as "slowing down programmers". http://research.swtch.com/generic

I think it's safe to say they are aware of the issue and consider lack of generics a negative (because it slows you down, duplicates code, adds type unsafety, etc.). They don't have a solution they like yet.

It would take more than:

(1) them not believing that Go has design issues

for my argument to not make sense. It would need both (1) and

(2) them being right about said belief

for my argument to be invalid. And while (1) might hold, (2) is highly debatable.