Generics are not a show stopper, since they already exist (built-in support) for everything the language creators care about.
Whether or not they are a show stopper for the users - well, that depends on your use case and preferences. Since show stoppers are a subjective thing. Objectively you could implement everything in Assembly or even Machine code, and people used to write rather complex programs this way.
I personally know there are a lot of types of systems I would never implement in Go if given the choice, because it would be too bothersome, and I don't like RSI. YMMV.
Whether or not they are a show stopper for the users - well, that depends on your use case and preferences. Since show stoppers are a subjective thing. Objectively you could implement everything in Assembly or even Machine code, and people used to write rather complex programs this way.
I personally know there are a lot of types of systems I would never implement in Go if given the choice, because it would be too bothersome, and I don't like RSI. YMMV.